JP2003163624A - Ttl relay system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a TTL relay system of simple constitution used in ground wave digital broadcasting, which is capable of canceling frequency errors generated at the time of frequency conversion inside a transmitter-receiver of the relay system and stably performing relay, and which can be constituted at a low cost. <P>SOLUTION: In the TTL relay system, by providing a reference signal distributor 24 supplying the same reference signal to frequency synthesizers 17 and 21 generating a local frequency in a repeater 2 and a receiver 5, generation of the local frequency is controlled so that the frequency error generated in the repeater 2 and the frequency error generated in the receiver 5 are of the same amplitude and their phases are reverse to each other. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TTL relay system in a TTL section used in a terrestrial digital broadcasting system, and more particularly to canceling a frequency error generated during frequency conversion in a transmitter / receiver of the relay system and stabilizing the same. The present invention relates to a TTL relay system that can be relayed to the Internet and can be configured at low cost.

[0002]

2. Description of the Related Art Terrestrial digital broadcasting is particularly applied to digital television broadcasting because it has a higher frequency utilization efficiency than conventional analog broadcasting and can transmit more information. Radio waves of digital terrestrial broadcasting are transmitted from the broadcasting station to a wireless transmission line (STL: Studio to Transmitter Link).
), A wireless transmission line (TTL: Transmit) that relays between the transmitting station and another transmitting station while being sent and delivered to the transmitting station.
ter to Transmitter Link) is delivered to a wide area via a broadcast program.

TT for digital terrestrial broadcasting according to the prior art
The L relay system will be described with reference to FIG. 4 as an example of a relay system that receives SHF broadcast radio waves and relays the SHF relay radio waves. FIG. 4 is a configuration block diagram of a conventional TTL relay system. In the conventional relay system in the TTL section, the broadcast radio wave f0 in the SHF band transmitted from the broadcasting station is used.
Is received by the antenna 1 installed at the transmitting station and sent to the relay device 1. In the relay device 1, the received signal f0 is I
It is F-converted and transmitted by relay radio wave f1 having different frequencies in the SHF band. At this time, in the relay device 1 in the transmitting station, a frequency error component Δf ′ is actually generated during frequency conversion,
The relay radio wave (f1 + Δf ′) is transmitted to the transmitting station on the receiving side, and the signal (f1 + Δf ′) received by the antenna 4 installed at the transmitting station has a frequency in the receiving device 5 as the broadcast radio wave f0 in the SHF band. To be converted. However, in reality, the frequency error Δf ″ during the frequency conversion inside the receiving device 5
Occurs, and the signal input to the demodulator 6 at the next stage is a signal in which the cumulative frequency error component (Δf ′ + Δf ″) is added to the original broadcast radio wave f0.

Normally, the demodulator 6 has an acceptable performance for the frequency error component of Δf ″ that can occur in the receiving device 5, but there is no guarantee that the accumulated error component of (Δf ′ + Δf ″) is acceptable. As a result, there is a possibility that the broadcast wave cannot be demodulated. To prevent this, the frequency error component Δf '
In order to suppress the problem as much as possible, it is necessary to enhance the accuracy and stability of the device, which results in an increase in cost.

The structure of a conventional relay device for suppressing the frequency error component Δf 'will be described with reference to FIG. FIG. 5 is a configuration block diagram of a conventional relay device.
In FIG. 5, the amplifiers equipped in the actual device are omitted. The relay device is installed at the transmitting station, as shown in FIG.
The broadcast radio wave f ₀ received from the antenna 1 of the SHF band from the broadcasting station of the SHF band is input to the band pass filter (BPF) 7 of FIG. 5 to remove unnecessary out-of-band signals, and then the local oscillator (OSC). The signal having the local frequency f _0LO generated in 9 is mixed in the mixer 8 and frequency converted. The broadcast signal converted into the local frequency is extracted by passing through the IF amplifier 10 and the BPF 11, and the OSC
The relay carrier f _TLO generated by 12 is mixed by the mixer 14 and frequency converted. The relay radio wave thus generated is transmitted as a relay radio wave f _T after removing unnecessary sideband signals in the BPF 15.

However, in an actual device, an error component exists in the local oscillation frequency, and f _0LO + Δ in _OSC9
The signal f _TLO + Δf _T ″ is generated at f ₀ ′ and OSC 12. As a result, the frequency error caused by having two different local oscillators in the conventional relay device shown in FIG. Δf ₀ ′ + Δ
the f T _". Thus, the it is possible to demodulate the receiving side of the demodulator 6, it is necessary to set the frequency error as small as possible. In the prior art relay apparatus, transmit and receive frequencies are the same frequency Band and local oscillator 9,1
2 is a frequency synthesizer, and the same reference signal for frequency generation is used so that Δf _O ′ and Δf _T ″ of frequency error components generated in the local oscillator have the same amplitude and opposite phase. By setting, the cumulative frequency error component was suppressed.

As one method for preventing fluctuations in the local oscillation frequency at each relay station, a technique using a pilot signal is disclosed in Japanese Patent Application Laid-Open No. 11-205280 “Transmission device and device” published on July 30, 1999. Receiver "
(Applicant: Japan Broadcasting Corporation, inventor: Yukio Tatsumi et al.). In this conventional technique, a pilot signal is superposed on the upper side (or lower side) of the spectrum forming the OFDM signal so that the frequency is slightly apart from the spectrum of the OFDM signal, and the signal is transmitted from the transmitting device, and at the receiving device side. The oscillation frequency of the local oscillator is controlled based on the pilot signal in the IF signal obtained by frequency-converting the transmission signal. This prevents fluctuations in the local frequency at each relay station. The OFDM signal can be surely frequency-converted or demodulated, and effective use of frequency and cost reduction can be achieved.

[0008]

However, in the conventional TTL relay apparatus shown in FIG. 5, since it is premised that frequency conversion is performed twice, the apparatus scale and cost increase, and the transmission and reception of broadcast radio waves and relay radio waves are performed. In a TTL relay system that uses different frequency bands, many relay devices generally have only one local oscillator from the viewpoint of device size and cost, and the relay device is used to suppress frequency error contained in a carrier wave. There has been a problem that the conventional technique which requires two local oscillators inside cannot be applied.

The present invention has been made in view of the above circumstances, and has a simple structure for use in terrestrial digital broadcasting.
It is an object of the present invention to provide a TTL relay system that can cancel a frequency error that occurs during frequency conversion in a transmitter / receiver of the relay system, can perform stable relay, and can be configured at low cost.

[0010]

DISCLOSURE OF THE INVENTION The present invention for solving the above-mentioned problems of the prior art is based on U in terrestrial digital broadcasting.
A relay device that receives the HF band broadcast radio wave, frequency-converts it to the SHF band relay radio wave, and transmits the radio wave to the receiving device in the next stage, and receives the SHF band relay radio wave and returns it to the original UHF band broadcast radio wave. In a TTL relay system including a receiving device that frequency-converts and demodulates, the relay device uses a common reference signal distributed from the reference signal transmitter by wire or wirelessly, or a frequency radio signal that is wirelessly standardly distributed. A frequency synthesizer that oscillates a first local frequency signal that is controlled according to a common reference signal that is generated from the mixer; and a mixer that performs frequency conversion by mixing the received broadcast radio wave in the UHF band and the first local frequency signal. The receiver is a relay device having a common reference signal distributed from the reference signal transmitter in a wired or wireless manner, or a frequency signal standardly distributed in a wireless manner. A frequency synthesizer that oscillates a second local frequency signal that is controlled according to a common reference signal that is generated from the signal, and a mixer that performs frequency conversion by mixing the received relay radio wave in the SHF band and the second local frequency signal. And controlling each local frequency in the relay device and the receiving device such that the error of the first local frequency and the error of the second local frequency have the same amplitude and opposite phases. Therefore, it is possible to cancel the frequency error that occurs during frequency conversion in the transmission / reception device of the relay system.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. The function realizing means described below may be any circuit or device as long as it can realize the function, and part or all of the function can be realized by software. is there. Further, the function realizing means may be realized by a plurality of circuits, or the plurality of function realizing means may be realized by a single circuit.

In the TTL relay system of the present invention, the relay device and the reception device have a common reference signal distributed by wire or wireless from the reference signal transmitter, or a frequency radio signal standardly distributed by wireless. Since the frequency conversion is performed by controlling the local frequency so that the errors have the same amplitude and opposite phase according to the common reference signal generated from, the frequency error generated during frequency conversion in the transmitter / receiver of the relay system is canceled. it can.

The configuration of the TTL relay system according to the first embodiment of the present invention will be described with reference to FIG. Figure 1
FIG. 3 is a configuration block diagram of a TTL relay system according to the first embodiment of the present invention. It should be noted that portions having the same configurations as those in FIGS. 4 and 5 will be described with the same reference numerals. As shown in FIG. 1, the TTL relay system (first relay system) according to the first exemplary embodiment of the present invention mainly includes a relay station A, a relay station B, and a reference signal transmitter 24. Has been done. In the relay station A, the reception antenna 1, the transmission antenna 3, the relay device 2 including the bandpass filter 16, the mixer 18, the frequency synthesizer 17, and the bandpass filter 19, and the reference signal receiver 25. It has and. Further, in the relay station B, a receiving device 5 including a receiving antenna 4, a bandpass filter 20, a mixer 22, a frequency synthesizer 21, and a bandpass filter 23, a demodulator 6, and a reference signal receiver. 26
It has and.

Then, the reference signal transmitter 24 and the relay station A
The reference signal receiver 25 is connected by a transmission line 27, and the reference signal transmitter 24 and the reference signal receiver 26 at the relay station B are connected by a transmission line 28. The reference signal transmitter 2
4 may be arranged in the relay station A, may be arranged in the relay station B, or may be provided in a third place other than the relay stations A and B. In any case, The effect is the same.

Next, each part of the first TTL relay system of the present invention will be described. The relay station A is a relay station that converts UHF band broadcast radio waves transmitted by STL from a terrestrial digital broadcasting station or the like into SHF band relay radio waves for relay transmission for TTL transmission. The relay station B is a relay station that receives the SHF band relay radio waves transmitted from the terrestrial digital broadcasting relay station by TTL, converts them into UHF band broadcast radio waves, and demodulates them. The reference signal transmitter 24 generates (oscillates) and transmits the reference signal fr in order to supply the same reference signal fr to the frequency synthesizer of the relay device 2 of the relay station A and the frequency synthesizer of the receiving device 5 of the relay station B. It is a device for. Transmission line 27,
And the transmission line 28 includes the reference signal transmitter 24 and the relay station A.
Reference signal receiver 25 of No. 2 or reference signal receiver 2 of relay station B
6 is a transmission line for distributing the same reference signal fr by connecting with 6, and a distribution facility by cable such as a cable or an optical fiber is installed.

Next, each part in the relay station A will be described. The receiving antenna 1 is a UHF transmitted from a broadcasting station or the like.
It is an antenna that receives band radio waves. The relay device 2 is
It is a device that frequency-converts the received UHF band broadcast radio wave and converts and transmits it to the SHF band relay radio wave. Transmitting antenna 3
Is an antenna for transmitting relay radio waves to the next relay station. The reference signal receiver 25 receives the same reference signal fr as the receiving device 5 transmitted from the outside, specifies the control voltage of the frequency synthesizer 17 described later based on the reference signal fr, and outputs the control voltage to the frequency synthesizer 17. Is.
Here, as a method of specifying the control voltage, in the present invention, the frequency error Δf ′ in the frequency synthesizer 17 has the same amplitude as the frequency error Δf ″ in the frequency synthesizer 21 of the receiver 5 of the relay station B, which will be described later, based on the reference signal fr. And a local frequency signal f that has an opposite phase
_The control voltage Vr1 for generating _LO1 + Δf ′ is specified and output.

Each section in the relay device 2 will be described. The band-pass filter 16 is a filter for selectively receiving UHF band broadcast radio waves. Frequency synthesizer 17
Is a device for generating a local frequency signal f _LO1 for frequency conversion into the SHF band, but the normal frequency error Δ
A component f'is generated. Therefore, in the present invention, the local frequency signal according to the control voltage Vr1 input from the outside is generated and output. Here, the local frequency signal according to the control voltage Vr1 has a frequency error Δf ′.
Is a local frequency signal of the local frequency signal f _LO1 + Δf ′ which has the same amplitude as the frequency error Δf ″ in the frequency synthesizer 21 of the receiving device 5 of the relay station B described later and has the opposite phase. It is a circuit that mixes the SHF band carrier wave and the received wave generated by the several number synthesizer 17 and frequency-converts it into a relay radio wave.The band pass filter 19 is a filter for selectively outputting the SHF band relay radio wave.

Next, each part in the relay station B will be described. The reception antenna 4 is an antenna that receives relay radio waves in the SHF band. The receiving device 5 is a device that frequency-converts the received SHF band relay radio wave and converts the frequency into a UHF band broadcast radio wave. The demodulator 6 is a circuit that demodulates the converted UHF band broadcast radio wave and converts it into an original broadcast signal. The reference signal receiver 26 receives the same reference signal fr as the relay device 2 transmitted from the outside, specifies a control voltage of the frequency synthesizer 21 described later based on the reference signal fr, and outputs the control voltage to the frequency synthesizer 21. Is. here,
As a method of specifying the control voltage, in the present invention, the reference signal fr
Based on the above, the local frequency signal f _LO2 + Δf ″ is such that the frequency error Δf ″ in the frequency synthesizer 21 has the same amplitude as the frequency error Δf ′ in the frequency synthesizer 17 of the repeater 2 of the relay station A and the opposite phase.
Is specified and output. Here, in practice, the reference signal receiver 25
The frequency error Δf ′ generated when the local frequency f _LO1 is generated based on the reference signal fr on the side is previously obtained by actual measurement, and the value of the frequency error Δf ′ is held on the side of the reference signal receiver 26. The frequency error Δf ″ generated when the reference signal receiver 26 generates the local frequency f _LO2 based on the reference signal fr has the same amplitude as the held frequency error Δf ′ and has the opposite phase. The control voltage Vr2 is controlled and output.

Each part in the receiving device 5 will be described. The band pass filter 20 is a filter for selectively receiving SHF band relay radio waves. Frequency synthesizer 21
Is a device for generating a local frequency signal f _LO2 for frequency conversion into the UHF band, but usually a frequency error Δ
Therefore, in the present invention, a local frequency signal according to the control voltage Vr2 input from the outside is generated and output. Here, the local frequency signal according to the control voltage Vr2 is Frequency error Δf ″
Is the frequency synthesizer 1 of the relay device 2 of the relay station A described above.
The local frequency signal f _LO2 + Δf ″ has the same amplitude as the frequency error Δf ′ in FIG. 7 and has the opposite phase. The mixer 22 mixes the local frequency generated by the frequency synthesizer 21 with the received wave. U
It is a circuit that performs frequency conversion into a signal that can be demodulated in the HF band.
The band pass filter 23 is a filter for selecting UHF band broadcast radio waves.

Next, the operation of the first TLL relay system of the present invention will be described. In the first TLL relay system of the present invention, the reference signal f generated by the reference signal transmitter 24 is used.
r is connected to the relay stations A and B via the transmission lines 27 and 28.
In the relay station A, the reference signal fr is received by the reference signal receiver 25, and the local frequency f _LO1 from the frequency synthesizer 17 includes the frequency error Δf ′ component in accordance with the reference signal fr.
_LO1 + Δf 'is generated. Similarly, at relay station B,
This reference signal fr is received by the reference signal receiver 26,
"Local frequency _{f LO2} + Delta] f in the form containing the component" frequency error Delta] f the local frequency _{f LO2} by frequency synthesizer 21 is generated in accordance with the reference signal fr.

Then, the broadcast radio wave f ₀ in the UHF band transmitted from the broadcasting station or the like is received by the receiving antenna provided in the relay station A.
It is received at 1 and input to the relay device 2. Then, in the relay device 2, only the broadcast radio wave component relayed by passing through the band pass filter (BPF) 16 in the UHF band is extracted from the broadcast radio wave f ₀ , and the frequency error Δf generated by the frequency synthesizer 17 is extracted. ' _Is mixed with the local frequency signal f _LO1 + Δf' by the mixer 18 and frequency-converted to the SHF band, and after passing through the SHF band-pass filter 19 to remove unnecessary frequency components, the transmission antenna 3 relays the SHF band. It is transmitted as radio wave f ₁ + Δf ′.

The relay radio wave f ₁ + Δf 'is received by the receiving antenna 4 at the relay station B and input to the receiving device 5 at the next stage. Then, inside the receiving device 5, the relay radio wave f ₁ + Δf ′ is transmitted to the band pass filter 20.
After extracting only the required relay radio wave, the local frequency signal f _LO2 + Δf ″ including the frequency error Δf ″ generated by the frequency synthesizer 21 is mixed in the mixer 22 and frequency-converted into the UHF band, After removing unnecessary frequency components through the band-pass filter 23, the signal is output to the demodulator 6 as UHF band broadcast radio wave f ₀ + Δf ′ + Δf ″, and demodulated by the demodulator 6 into a broadcast signal.

At this time, the frequency synthesizer 17 of the relay device 2 of the relay station A and the frequency synthesizer 21 of the receiver device 5 of the relay station B respectively follow the same reference signal fr distributed from the reference signal transmitter 24. Since the generation of the local frequency is controlled so that the generated frequency errors Δf ′ and Δf ″ have the same amplitude and opposite phases,
UHF band broadcast radio wave f ₀ + Δ output from the receiving device 5
The cumulative frequency error component of transmission / reception at f ′ + Δf ″ (Δ
f ′ + Δf ″) is suppressed, and the UHF band broadcast radio wave f ₀ is input to the demodulator 6 and demodulated.

In the above description, the reference signal receivers 25 and 26 are provided with the function of specifying the local frequencies so that the frequency errors Δf ′ and Δf ″ from the reference signal fr have the same amplitude and opposite phases. But the reference signal receiver 25,2
Reference numeral 6 simply outputs a reference voltage according to the reference signal fr, and the frequency synthesizers 17 and 21 generate frequency errors Δf ′ and Δ.
The local frequencies may be determined and output so that f ″ has the same amplitude and opposite phases.

According to the first TLL relay system of the present invention, the same reference signal fr generated by the reference signal transmitter 24 is distributed through a wired transmission line, and the control voltage is specified according to the reference signal fr. Repeater 2 and receiver 5
By controlling the output of the frequency synthesizer so that the frequency errors Δf ′ and Δf ″ when the local frequency signals are generated by the frequency synthesizers 17 and 21 have the same amplitude and opposite phase, The cumulative frequency error (Δf ′ + Δf ″) that occurs can be totally suppressed (canceled) by the relay device 2 and the reception device 5, and the relay system as a whole can stably relay and demodulate radio waves. effective.

A TLL relay system according to a second embodiment of the present invention to which the above-described first relay system of the present invention is applied will be described with reference to FIG. FIG. 2 is a configuration block diagram of a TTL relay system according to the second embodiment of the present invention. It should be noted that parts having the same configurations as those in FIG. Second of the present invention
As shown in FIG. 2, the TLL relay system (second relay system) according to the embodiment of the present invention largely includes a relay station A, a relay station B, and a transmitting antenna 33, as in the first relay system. And a reference signal transmitter 24.
However, in the first relay system, the reference signal transmitter 24 delivered the reference signal to the relay station A and the relay station B by wire connection, but in the second relay system, the reference signal is relayed by the radio wave. They are different in that they are distributed to A and relay station B. The reference signal transmitter 24 may be arranged in the relay station A, the relay station B, or other than the relay stations A and B, as in the first relay system. It may be provided in the third place, and the effect is the same in any case.

In the relay station A, the receiving antenna 1
The relay device 2 includes a transmission antenna 3, a bandpass filter 16, a mixer 18, a frequency synthesizer 17, and a bandpass filter 19, and a reception antenna 29 and a reference signal receiver 30. Further, in the relay station B, a receiving device 4 including a receiving antenna 4, a bandpass filter 20, a mixer 22, a frequency synthesizer 21, and a bandpass filter 23, a demodulator 6, and a receiving antenna 31. And a reference signal receiver 32.
The receiving antenna 1 and the receiving antenna 29 of the relay station A and the receiving antenna 4 and the receiving antenna 31 of the relay station B are shared, and the effect of the present invention is not changed even if either antenna is omitted.

Next, each part of the second TTL relay system of the present invention will be described. The receiving antenna 1, the transmitting antenna 3, the relay device 2 at the relay station A, and the receiving antenna 4 and the receiving device 5 at the relay station B are described. , Demodulator 6 is the first
Since it is exactly the same as that of the relay system, the description thereof is omitted here, and only the characteristic part will be described. The receiving antenna 29 of the relay station A is an antenna that receives a radio wave of the reference signal fr wirelessly transmitted from the reference signal transmitter 24. The reference signal receiver 30 receives the same reference signal fr as the receiving device 5 wirelessly received via the antenna 29, and the frequency error Δf ′ in the frequency synthesizer 17 causes the frequency of the receiving device 5 at the relay station B to be described later. The control voltage Vr1 that produces the local frequency signal f _LO1 + Δf ′ that has the same amplitude as the frequency error Δf ″ in the synthesizer 21 and has the opposite phase is specified and output to the frequency synthesizer 17.

The receiving antenna 31 of the relay station B is an antenna for receiving the radio wave of the reference signal Vr wirelessly transmitted from the reference signal transmitter 24. The reference signal receiver 32 receives the same reference signal fr as that of the relay device 2 wirelessly received via the antenna 31, and the frequency error Δf ″ in the frequency synthesizer 21 is the frequency of the relay device 2 of the relay station A described above. A local frequency signal f having the same amplitude as the frequency error Δf ′ in the synthesizer 17 and an opposite phase.
_The control voltage Vr2 that generates _LO2 + Δf ″ is specified and output to the frequency synthesizer 21.

Next, the operation of the second TLL relay system of the present invention will be described. In the second TLL relay system of the present invention, the reference signal f generated by the reference signal transmitter 24 is used.
r is wirelessly transmitted via the transmitting antenna 33, and the relay station A
Then, the transmitted radio wave of the reference signal fr is received by the receiving antenna 29.
The control voltage Vr1 that is received by the reference signal receiver 30 via the reference signal fr and is capable of canceling the frequency error according to the reference signal fr is output to the frequency synthesizer 17 of the repeater 2, and the frequency synthesizer 17 outputs the local frequency f.
Frequency error Delta] f 'forms containing the component local frequency _{f LO1} + Δf' is generated in _LO1. Similarly, at the relay station B, the radio wave transmitted by the reference signal fr is received by the receiving antenna 3
1 is received by the reference signal receiver 26, and the control voltage Vr2 capable of canceling the frequency error according to the reference signal fr is output to the frequency synthesizer 21 of the receiving device 5, and the frequency synthesizer 21 outputs the local frequency f.
Frequency error Delta] f "form containing the component local frequency _{f LO2} + Δf" is generated in the _LO2.

The frequency conversion operation at the relay stations A and B is similar to that of the first relay system of the present invention described with reference to FIG. 1, and the broadcast radio wave f ₀ in the UHF band transmitted from the broadcasting station or the like is used. Is the frequency synthesizer 1 in the relay device 2.
7 is mixed with the local frequency signal f _LO1 + Δf ′ including the frequency error Δf ′ generated by S.
Frequency converted to HF band, SHF band relay wave f ₁ + Δ
Sent as f '. Then, the relay radio wave f ₁ + Δf ′
Is the local frequency signal f including the frequency error Δf ″ generated by the frequency synthesizer 21 at the relay station B.
_{The LO2} + Δf ″ is mixed by the mixer 22 and frequency-converted to the UHF band, and the UHF band broadcast radio wave f ₀ + Δf ′ + Δ
It is output to the demodulator 6 as f ″.

At this time, similarly to the first relay system of the present invention, the frequency synthesizer 17 of the relay device 2 of the relay station A is used.
And the frequency synthesizer 21 of the receiver 5 of the relay station B
Then, in accordance with the same reference signal fr distributed from the reference signal transmitter 24, the frequency error Δf ′ generated in each of them,
Since the generation of the local frequency is controlled so that Δf ″ has the same amplitude and the opposite phase, the accumulated frequency error component of transmission / reception in the UHF band broadcast radio wave f ₀ + Δf ′ + Δf ″ output from the receiving device 5. (Δf ′ + Δf ″) is suppressed, and the UHF band broadcast radio wave f ₀ is input to the demodulator 6 and demodulated.

In the above description, the reference signal receivers 30 and 32 have the function of specifying the local frequencies so that the frequency errors Δf ′ and Δf ″ from the reference signal fr have the same amplitude and opposite phases. But the reference signal receiver 30,3
The reference numeral 2 simply outputs a reference voltage according to the reference signal fr, and the frequency errors Δf ′, Δ
The local frequencies may be determined and output so that f ″ has the same amplitude and opposite phases.

According to the second TLL relay system of the present invention, the same reference signal fr generated by the reference signal transmitter 24 is distributed by radio waves, and the relay device 2 and the relay device 2 are transmitted using the reference signal fr. Each frequency synthesizer 1 of the receiver 5
By controlling the output of the frequency synthesizer so that the respective frequency errors Δf ′ and Δf ″ when the local frequency signal is generated in 7 and 21 have the same amplitude and opposite phase, the cumulative frequency generated during frequency conversion is generated. Error (Δf ′ +
[Delta] f ") can be totally suppressed (cancelled) by the relay device 2 and the receiving device 5, and a stable radio wave can be relayed and demodulated as a whole relay system. In the second relay system of No. 1, it is not necessary to lay cables or the like of the transmission lines 27 and 28 that connect the reference signal transmitter 24 and the reference signal receiver 25 or the reference signal receiver 26 provided in the first relay system. Therefore, there is an effect that the device can be simplified.

A TL according to a third embodiment of the present invention to which the first and second relay systems of the present invention described above are applied.
The L relay system will be described with reference to FIG. Figure 3
FIG. 9 is a configuration block diagram of a TTL relay system according to a third embodiment of the present invention. It should be noted that parts having the same configurations as those in FIGS. 1 and 2 are described with the same reference numerals.
As shown in FIG. 3, the TLL relay system (third relay system) according to the third exemplary embodiment of the present invention mainly includes a relay station A and a relay station B.

In the relay station A, the receiving antenna 1
The relay device 2 includes a transmission antenna 3, a bandpass filter 16, a mixer 18, a frequency synthesizer 17, and a bandpass filter 19, a reception antenna 29, and a standard radio wave receiver 34. Further, in the relay station B, a receiving device 4 including a receiving antenna 4, a bandpass filter 20, a mixer 22, a frequency synthesizer 21, and a bandpass filter 23, a demodulator 6, and a receiving antenna 31. The standard radio wave receiver 35 is provided.
The receiving antenna 1 and the receiving antenna 29 of the relay station A and the receiving antenna 4 and the receiving antenna 31 of the relay station B are shared, and the effect of the present invention is not changed even if either antenna is omitted.

Next, each part of the third TTL relay system of the present invention will be described. The receiving antenna 1, the transmitting antenna 3, the relay device 2 at the relay station A, and the receiving antenna 4 and the receiving device 5 at the relay station B are described. , Demodulator 6 is the first
Since it is exactly the same as that of the relay system, the description thereof is omitted here, and only the characteristic part will be described. The receiving antenna 29 of the relay station A and the receiving antenna 31 of the relay station B are JJY (standard frequency radio waves of a standard time supply system transmitted by a standard frequency station operated by the Ministry of Posts and Telecommunications Research Institute) or GP.
This is an antenna for receiving standard frequency radio waves fstd such as S (Global Positioning System) time matching radio waves. The reference signal receiver 34 of the relay station A reproduces the reference signal fr based on the standard frequency radio wave fstd wirelessly received through the antenna 29 or the antenna 31, and the frequency synthesizer 1
The control voltage of 7 is specified and output to the frequency synthesizer 17. Here, as a method of specifying the control voltage,
In the present invention, the reference signal fr is reproduced based on the standard frequency radio wave fstd, and the frequency error Δf ′ in the frequency synthesizer 17 has the same amplitude as the frequency error Δf ″ in the frequency synthesizer 21 of the receiving device 5 at the relay station B, and the inverse. The control voltage Vr1 that generates the local frequency signal f _LO1 + Δf ′ that is in phase is specified and output.

Similarly, the reference signal receiver 35 of the relay station B
Is to reproduce the reference signal fr based on the standard frequency radio wave fstd wirelessly received via the antenna 31, specify the control voltage of the frequency synthesizer 21, and output it to the frequency synthesizer 21. Here, as a method of identifying the control voltage, in the present invention, the reference signal fr is reproduced based on the standard frequency radio wave fstd, and the frequency error Δf ″ in the frequency synthesizer 21 causes the frequency synthesizer 17 of the relay device 2 of the relay station A to be described above. Of the local frequency signal f having the same amplitude as the frequency error Δf ′ at
_The control voltage Vr2 that generates _LO2 + Δf ″ is specified and output.

Next, the operation of the third TLL relay system of the present invention will be described. In the third TLL relay system of the present invention, the frequency synthesizer 17 of the relay device 2 of the relay station A is used.
And the frequency synthesizer 21 of the receiver 5 at the relay station B,
As a system for delivering the same reference signal fr,
As an alternative to providing the reference signal transmitter 24 in the second system, a standard frequency radio wave such as JJY or a standard radio wave fstd such as a GPS time matching signal is received by the receiving antenna 29.
And the reception antenna 31 receives. The same received standard radio wave fstd is received by the standard radio wave receiver 34 and the standard radio wave receiver 35, and the reference signal fr is reproduced using the standard radio wave receiver 34 and the standard radio wave receiver 35, and the frequency error Δf ′ in the frequency synthesizer 17 is based on the reference signal fr. Is the receiving device 5 at relay station B
The control voltages Vr1 and Vr2 that generate local frequency signals having the same amplitude as the frequency error Δf ″ in the frequency synthesizer 21 and having the opposite phase are specified and output to the frequency synthesizers 17 and 21, respectively. going on. Then, in the relay stations a, relay device 'local frequency f _{LO1 +} Delta] f in the form containing the components' frequency error Delta] f the local frequency f _LO1 at a second frequency synthesizer 17 is generated in accordance with the control voltage Vr1, Similarly To
In the relay stations B, local frequency _f of forms including frequency error Delta] f "component in the local frequency _{f LO2} by frequency synthesizer 21 of the receiver 5 in accordance with the control voltage Vr2 _LO2
+ Δf ″ is generated.

The frequency conversion operation at the relay station A and the relay station B is the same as that of the first relay system of the present invention described in FIG. 1, and the broadcast radio wave f ₀ in the UHF band transmitted from a broadcast station or the like. Is the frequency synthesizer 1 in the relay device 2.
7 is mixed with the local frequency signal f _LO1 + Δf ′ including the frequency error Δf ′ generated by S.
Frequency converted to HF band, SHF band relay wave f ₁ + Δ
Sent as f '. Then, the relay radio wave f ₁ + Δf ′
Is the local frequency signal f including the frequency error Δf ″ generated by the frequency synthesizer 21 at the relay station B.
_{The LO2} + Δf ″ is mixed by the mixer 22 and frequency-converted to the UHF band, and the UHF band broadcast radio wave f ₀ + Δf ′ + Δ
It is output to the demodulator 6 as f ″.

At this time, similarly to the first relay system of the present invention, the frequency synthesizer 17 of the relay device 2 of the relay station A is used.
And the frequency synthesizer 21 of the receiver 5 of the relay station B
Then, the same reference signal fr is reproduced on the basis of the standard frequency radio wave fstd, and the frequency errors Δf ′ and Δf ″ generated in each are reproduced in accordance with the reference signal fr so as to have the same amplitude and opposite phases to each other. Since the generation is controlled, the UHF band broadcast radio wave f ₀ output from the receiving device 5
The accumulated frequency error component (Δf ′ + Δf ″) of transmission / reception at + Δf ′ + Δf ″ is suppressed, and the demodulator 6 receives UHF.
The band broadcast radio wave f ₀ is input and demodulated.

In the above description, the standard frequency radio wave fstd
The common reference signal fr is reproduced based on
Therefore, the reference radio wave receivers 34 and 35 are provided with the function of specifying the local frequencies so that the frequency errors Δf ′ and Δf ″ have the same amplitude and opposite phases to each other. The common reference signal fr is simply reproduced on the basis of the standard frequency radio wave fstd, and the reference voltage according to the reference signal fr is output. In the frequency synthesizers 17 and 21, the frequency errors Δf ′ and Δf ″ have the same amplitude and are mutually equal. The local frequency may be determined and output so as to have the opposite phase.

According to the third TLL relay system of the present invention, the same standard signal fstd of JJY, GPS or the like is used to generate the same reference signal fr in the standard wave receivers 34 and 35, and the reference signal fr is generated. Each frequency error Δf ′, Δ when a local frequency signal is generated by each frequency synthesizer 17, 21 of the relay device 2 and the receiving device 5 using fr.
By controlling the output of the frequency synthesizer so that f ″ has the same amplitude and the opposite phase, the cumulative frequency error (Δf ′ + Δf ″) generated during frequency conversion is combined by the relay device 2 and the receiving device 5. Suppressed (cancelled)
Thus, the relay system as a whole can stably relay and demodulate radio waves. In addition, in the third relay system of the present invention, the cables of the transmission lines 27 and 28 that connect the reference signal transmitter 24 and the reference signal receiver 25 or the reference signal receiver 26 provided in the first relay system, etc. Is unnecessary, and the reference signal transmitter 24 and the transmitting antenna 33, which are provided in the second relay system, are also unnecessary. Therefore, the device can be further simplified.

In the above-described embodiment, the case where the relay device and the receiving device are one set has been described, but the present invention is implemented for the TTL relay system including a plurality of relay devices and receiving devices. Even in some cases, the effect is the same.

[0045]

According to the present invention, the frequency synthesizer of the relay device is a common reference signal distributed from the reference signal transmitter by wire or wirelessly, or a frequency radio wave signal standardly distributed by wireless. Oscillates a first local frequency signal controlled in accordance with a common reference signal generated from the mixer, mixes the UHF band broadcast radio wave received by the mixer with the first local frequency signal, performs frequency conversion, and receives The frequency synthesizer of the device is controlled according to a common reference signal distributed from the reference signal transmitter by wire or wirelessly, or a common reference signal generated from a frequency radio signal normally distributed by wireless. The first local frequency is generated by oscillating the second local frequency signal, mixing the received relay radio wave in the SHF band with the second local frequency signal, and performing frequency conversion. And error, T and error of the second local frequency is the same amplitude, to control the respective local frequency in the relay apparatus and the receiving apparatus so that the antiphase
Since the TL relay system is used, there is an effect that a frequency error generated at the time of frequency conversion in the transmitter / receiver of the relay system can be canceled, stable relay can be performed, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a first TTL relay system according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of a second TTL relay system according to the exemplary embodiment of the present invention.

FIG. 3 is a configuration block diagram of a third TTL relay system according to an embodiment of the present invention.

FIG. 4 is a block diagram of a conventional relay system configuration in a TTL section.

FIG. 5 is a block diagram of a relay device according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Receiving antenna, 2 ... Relay apparatus, 3 ... Transmitting antenna, 4 ... Receiving antenna, 5 ... Receiving apparatus, 6 ... Demodulator, 7 ... Band pass type filter, 8 ... Mixer, 9
... local oscillator, 10 ... IF amplifier, 11 ... bandpass filter, 12 ... local oscillator, 13 ... relay device,
14 ... Mixer, 15 ... Bandpass filter (BP
F), 16 ... UHF band bandpass filter, 17 ...
Frequency synthesizer, 18 ... Mixer, 19 ... SH
F band band pass filter, 20 ... SHF band band pass filter, 21 ... Frequency synthesizer, 22 ... Mixer, 23 ... UHF band band pass filter, 24 ...
Reference signal transmitter, 25 ... Reference signal receiver, 26 ...
Reference signal receiver, 27 ... Transmission line, 28 ... Transmission line,
29 ... Receiving antenna, 30 ... Reference signal receiver, 31
... reception antenna, 32 ... standard signal receiver, 33 ... transmission antenna, 34 ... standard radio receiver, 35 ... standard radio receiver

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C056 FA01 GA05 HA01 HA04 HA13                       HA15                 5K020 AA02 BB05 DD22 FF00 GG01                       GG21 HH13 NN07                 5K072 AA18 BB14 BB25 DD15 EE21                       FF06 GG39

Claims (3)

[Claims] 1. A relay device for receiving broadcast radio waves in the UHF band in terrestrial digital broadcasting, frequency-converting the relay radio waves in the SHF band, and transmitting the radio waves to a receiving device in the next stage;
In a TTL relay system including a receiving device that receives a relay radio wave in the HF band, frequency-converts it into an original UHF band broadcast radio wave, and demodulates the relay device, the relay device is controlled according to a reference signal distributed from the outside. A relay device having a frequency synthesizer that oscillates a local frequency signal, and a mixer that performs frequency conversion by mixing the received broadcast radio wave in the UHF band and the first local frequency signal, wherein the receiving device is externally connected. A frequency synthesizer that oscillates a second local frequency signal that is controlled according to the reference signal that is distributed, and a mixer that performs frequency conversion by mixing the received relay radio wave in the SHF band and the second local frequency signal. A receiving device having, wherein the error of the first local frequency and the error of the second local frequency have the same amplitude, TTL relay system and controls the respective local frequency in the relay apparatus and the receiving apparatus such that the phase. 2. A reference signal transmitter for transmitting a common reference signal, wherein the relay device and the reception device receive a reference signal distributed by wire or wireless from the reference signal transmitter, The relay device and the receiving device having a reference signal receiving means for outputting a control voltage for controlling the local frequency of the frequency synthesizer based on the reference signal.
The described TTL relay system. 3. The relay device and the receiving device receive a common frequency radio wave signal that is wirelessly standardly distributed, generate a reference signal from the frequency radio wave signal, and generate a local signal of the frequency synthesizer based on the reference signal. 2. The TT according to claim 1, which is a relay device and a reception device having a reference signal generating means for outputting a control voltage for controlling the frequency.
L relay system.