JPS59151539A - Radio signal receiving system - Google Patents

Abstract

PURPOSE:To reduce the length of cable and to miniaturize a device for the titled system by providing separately IF amplifiers and providing the amplifier near each mixer. CONSTITUTION:The 1st mixers 14, 22, the 1st local oscillating circuits 16, 24 and the IF amplifiers 18, 26 are connected respectively to an X band antenna 10 and a K band antenna 12. The horn of the antennas 10, 12 includes in the inside mixing gun diodes 14, 22 and oscillating gun diodes 16, 24 respectively. The output of the diodes 14, 22 is given to the respective IF amplifiers 18, 26, and the output of the IF amplifiers is added by a line 66.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wireless signal receiving system that can be applied to a device that detects the presence of electromagnetic waves such as X- and N-band radar signals.

The U.S. FCC (Federal Communications Commission) defines the X band loop signal as 10.525 GHz±0.025 GHz, and the second band loop signal as 24.150 GHz±0.025 GHz.
It is set at 0.100 GHz. Often it is necessary to filter out the presence of signals in these bands in the form of CW or pulsed waves.

Various methods have been developed in the past. however.

It is still unsatisfactory to detect these weak signals in degrees Celsius using low-cost equipment.

The reception method to which the present invention is applied is □, 1.033GH if kept.
When taking out the first mixer output of z, if a signal of 7 times the radio wave of an amateur frequency node of 144 Mflz is generated in this mixer output, it is difficult to distinguish whether this is a signal wave from the antenna or an interference wave. Therefore, a key signal such as a pilot signal is inserted into the antenna output at #!j, and only the signal containing the key signal of C is used as a detection signal.For this purpose, the pilot signal is the first mixed signal. The first local oscillator signal is frequency modulated and inserted into the first local oscillator signal.

This intermediate frequency amplified heterotine signal is further heterodyned with the frequency swept second local oscillation signal in a second mixer. This second mixer output is applied to a first bandpass filter. The second mixer output, whose frequency is varied by the frequency sweep signal, is output from the first BPF when it enters the pass frequency range of the first BPF, these intermittent outputs are then demodulated by a frequency discriminator, and the tone bursts of the pilot signal are Detected. These tone burst signals are provided to the second BPF. The output of a narrowband BPF with a passband at the pilot signal frequency is phase compared with a continuous high lot signal in a phase-locked loop. The locked state of the phase-locked loop' is detected by the reception instruction means.

The present invention aims to improve the circuit configuration of the first mixer stage and the intermediate frequency amplifier stage in view of the above-mentioned system processing high frequency signals of giga-hertz scale, and in view of the demand for miniaturization. That is.

FIG. 1 is a block diagram of a microwave reception system incorporating the present invention. In this system, X-band and 2-band CW or pulsed electromagnetic radiation signals are configured to be received by the first antenna 10 and the second antenna, respectively. X) (nd is 10.500 to 10.5
It covers frequencies from 50G (giga) to 24.05GHz, and the band is regulated to cover 24.050 to 24-250GHz '17. X
The signal from 0 is heterogained with the local oscillator signal from local oscillator 16 to 1. The current signal from the oscillator 16 is in the form of a 9,492 GHz signal frequency modulated with a 19 KHz pilot signal, as will be described later. The output from mixer 14 is connected to an IP amplifier 18, which is tuned to amplify the (1,033±0.025) GHz signal. The amplified signal from IF amplifier 18 is provided to the input of a common amplifier constellation.

It is connected to the X-band antenna 12. 1 mixer n,
The five circuits comprising the first local oscillator and the IF amplifier series whose outputs are connected to the other inputs of the common amplifier series are substantially identical in construction to the circuits described above with respect to the X-band antenna 10. , the output of the second local oscillator blade is 19 KH as mentioned above.
z nokuirot signal and frequency modulated 2 3.117
GH2 and the heterodyne output from the first mixer ρ is at a frequency of (1,033±0.100) GHz.

The output of the common thickener is connected to a second mixer section. Therefore, this second mixer has X/((1.033±0.025 for the band microwave))
) It is now possible to receive GHz IP signal.

Also received by the second mixer 4 is the second local oscillator signal from the second local oscillator blade.

The frequency of this oscillator signal is 9.983~1.083 G
It can vary continuously between Hz. The rate at which such a frequency range is swept is determined by the blade Hz from the sweep generator 32.
determined by the sawtooth waveform. In order to sweep the frequency of the second local oscillation signal, a triangular wave or the like may be used instead of the above-mentioned sawtooth wave. The second mixer 28 is 1.033 GH
This variable frequency local oscillator is swept by the IF signal 'lj (30 Hz) of z (30 Hz)-X sweep signal for hetero gain.

A 10.7 MHz first bandpass filter (BPF) 34 coupled to the second mixer 4 has a second mixer output of 10.7 M
According to the frequency range of the center frequency of Hz.

Let it pass. This frequency range is required in the operation of a phase-locked loop (PLL), which will be described later. The output of the 1lBPF 34 is amplified by a 10.7 MH2 tuned amplifier 34 and applied to a discriminator. This discriminator detects an intermittent 19 kHz high-lot signal when the microwave receiving system is receiving a band wave in X or 5.
The tone signal is designed to repeat. These 19
The period of occurrence of the KHz pilot tone depends on the frequency of the sweeping sawtooth wave generated by sweep generator 32.

The demodulated intermittent pilot signal is 19 KHz narrow range B.
PF4 (1-pass). This BPF4tJ lacks a passband of 19 KHz to 8100 Hz in the preferred embodiment.

The output of this 28th PF is amplified by amplifier 4],
Phase Lock Roof' (PLL) 42 to 4
．． t be beaten. The illustrated PLL 42 is a voltage controlled oscillator (VCO) 44. Phase comparator and low pass filter 4
8. The VCO 44 provides a 19 KHz continuous signal on the line mark, which is amplified by an amplifier 52 and then provided to the first local oscillator 16 and the second band for frequency modulation in the KX and X bands. When a signal in the 19 KHz or 2 band is received by the illustrated receiving scheme, an intermittent signal in the form of a 19 KHz)-on burst train
A KHz 3-tone pilot signal is generated at the PLL, input line. This intermittent demodulated pilot signal is sent to the phase comparator 4.
6 is compared in phase with the continuous VCO output from VCO 44, which is identical to the continuous pilot signal to be modulated by one frequency. The result of this comparison causes a switch 56 connected to the PLL output to operate between the buzzer drive circuit and the lamp drive circuit to provide an audible and visible indication of reception of the X band and Y band signals. The low pass filter 48 of the PLL block ensures that even though there is some phase difference between the continuous pilot signal to be frequency modulated and the intermittent demodulated pilot signal, each demodulated pilot burst contains only a small number of burst pulses. Even if it's not P
It operates to bring LL42' into its locked state. The wider the band of the 10.7MHz BIPF34, the more bursts there will be in each pilot tone burst.
It is possible to include many pulses. However, widening the band of BPF 34 will reduce the sensitivity of the pilot signal servo loop. In the preferred embodiment, P
I found out that LL42 locks stably. This provides a narrow passband for the first BPF 34 and a large pilot signal servo gain.

By using a narrow band 19 KHz O) B P F 40 k.

A high S/N ratio is provided. In the reception method of the present invention for detecting tone signals, it is possible to make the reception frequency band four-dimensionally small and provide high-sensitivity performance. Yet again. Since only the signals passing through the first mixer 14 and η are frequency modulated with the pilot signal, the system of the present invention does not react to spurious or noise that enters after these first mixers.

FIG. 2 shows the X-band antenna 10 of FIG. band in
Antenna 12. First mixer 14, 22, first local oscillator circuit 1
6.24 and a detailed circuit diagram of the intermediate frequency amplifiers 18, 26 are shown. The antenna horn 10.12 includes within it a mixer Gunn diode 14.22 and an oscillator Gunn diode 16.18. Oscillator Gunn diode 16 is biased at 5.degree. via power line 62 and oscillator Gunn diode U is biased at 8.degree. The pilot signal from the line bar superimposed on these DC bias voltages has an AC waveform such as a sine wave or a triangular wave. Respective mixer gun diodes 14,2
The outputs of the two intermediate frequency amplifiers are applied to respective intermediate frequency amplifiers 18 and 26, and the outputs of these intermediate frequency amplifiers are summed on line 66.

It is intended to be applied between the common amplifiers of FIG.

By separately providing intermediate frequency amplifiers 18 and 26, -
These two amplifiers can be placed near their respective mixers, thus making it possible to shorten the length of cables between these mixers and amplifiers, and increasing the degree of freedom in installing the horn itself. be able to. This greatly contributes to the miniaturization of the device and the shape of the housing of the device, and to the improvement of circuit performance.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a partial circuit diagram thereof. 10 is an X-band horn antenna, 12 is a band-horn antenna, 14.22 is a Gunn diode first mixer, 16° is a Gunn diode first local oscillator, and 18.26 is an intermediate frequency amplification vessel, 2
8 is a second mixer, 30 is a second local oscillator, 32 is a sweep signal generator, 34 is a first bandpass filter, 38 is a discriminator, 40 is a second bandpass filter, 42 is a phase-locked loop, 58 Reference numeral 60 indicates a buzzer drive circuit, and 60 indicates a lamp drive circuit.

Claims (1)

[Claims] Antenna means corresponding to each frequency band for receiving radio frequency signals within a plurality of frequencies and wave number bands, and a first station transmitter connected to each antenna means and frequency modulated with a continuous pilot signal. a first mixer for heterodyning said radio frequency signal with a signal to provide an intermediate frequency signal; and a tuned amplifier connected to each first mixer for amplifying said intermediate frequency signal. Means for connecting the outputs of these tuned amplifiers, a tuning amplifier can receiver from the output connecting means, and a second local oscillator signal swept with a frequency sweep signal of a predetermined sweep speed to output the tuned amplifier. a second mixer for heterogaining the
a first band-pass filter that receives the output of the second mixer, has a passband in a predetermined frequency range, and passes this part when the output of the second mixer falls within the frequency range of the passband; The output of this first bandpass filter is
Frequency demodulate this and record the tone of the pilot signal.
a discriminator for extracting the tone burst of the high-lot signal, a second band-pass filter that receives and passes the tone burst of the high-lot signal and has a narrow pass band characteristic χ, a voltage-controlled oscillator that generates the continuous pilot signal, and a voltage-controlled oscillator that generates the continuous pilot signal. and pylon 1 from the second bandpass filter above.
A phase comparator that compares the phase of the tone burst, and a low-pass filter that controls the voltage controlled oscillator based on the output of the phase comparator and the result of the comparison. and means for indicating reception of the radio frequency signal in response to the output of the phase comparator. A radio signal receiving system characterized in that each of the antenna means comprises a horn antenna, and each of the first mixers comprises a Gunn diode housed in each of the horn antennas.