JP2005051594A - Frequency converter, receiver and transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frequency converter small in size and reduced in consumption electric current by decreasing the number of circuits in a high-frequency transmitting and receiving apparatus by using a frequency divider as a part of the frequency converter. <P>SOLUTION: The converter is equipped with an n-frequency divider for dividing a frequency of an oscillating signal from a local oscillator and a high-frequency signal input for inputting a high-frequency signal. The n-frequency divider divides the frequency of the input local oscillating signal into 1/n pieces of frequencies and then inputs the high-frequency signal from the high-frequency signal input, outputting a mixed signal of a frequency component of the high-frequency signal and the 1/n pieces of frequencies. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a frequency converter used in a radio transceiver and a radio transceiver using the frequency converter.

  For example, in a conventional frequency converter described in a patent publication (Japanese Patent Laid-Open No. 2000-31854) and a receiving system using the same, a signal output from an oscillator is used as a local oscillation signal of the frequency converter as shown in FIG. The frequency is divided by a frequency divider and used.

  In FIG. 10, 25 is an antenna, 26 is a low noise amplifier, 27 is a band pass filter, 28 is a first frequency converter for converting a high frequency signal to an intermediate frequency, and 29a and 29b convert the intermediate frequency signal to a baseband frequency. Second frequency converter, 30a and 30b are low-pass filters, 31a and 31b are baseband amplifiers, 32 is a decoder, 33 is a local oscillator, 34 is a frequency divider, 35 is a 90-degree distributor, and 36 is an output terminal. It is.

  The operation will be described below. The received signal received by the antenna 25 is amplified by the low noise amplifier 26, and then an unnecessary frequency is filtered by the band pass filter 27 and input to the first frequency converter 28. The first frequency converter 28 mixes with the local oscillation signal output from the local oscillator 33 and outputs it as an intermediate frequency (IF) signal to the second frequency converters 29a and 29b. On the other hand, the local oscillation (LO) signal output from the local oscillator 33 is frequency-divided by the frequency divider 34, and is divided into two orthogonal signals of 0 degrees and 90 degrees by the 90-degree distributor 35, and the second frequency. Input to the converters 29a and 29b. In the second frequency converters 29a and 29b, the LO signal is mixed with the IF signal and converted into a baseband signal. The converted baseband signal is input to the decoder 32 via the low pass filters 30a and 30b and the baseband amplifiers 31 and 31b.

  Although the conventional technique has been described with respect to the example in which the 90-degree distributor 35 is provided at the subsequent stage of the frequency divider 34, the first frequency converter 28 that converts a high-frequency signal into an intermediate frequency is another conventional technique. Some are provided in the latter stage.

JP 2000-31854 A

  In the conventional frequency converter and receiving system as described above, when the frequency of the local oscillator is high, before the local oscillation signal is input to the frequency converter, a frequency division by the frequency divider is required. There is a problem that the number of circuits increases and the current consumption increases.

  The present invention has been made to solve the above-described problems. By using a frequency divider as a part of the frequency converter, the frequency of the small-sized and low current consumption is reduced by reducing the number of circuits in the high-frequency transceiver. The purpose is to realize a converter.

  A frequency converter according to the present invention includes an n frequency divider that divides an oscillation signal from a local oscillator and a high frequency signal input unit that inputs a high frequency signal, and the n frequency divider receives the input local oscillation signal. Is divided into 1 / n frequency, a high frequency signal is input from the high frequency signal input unit, and a mixed signal of the frequency component of the high frequency signal and the 1 / n frequency is output. is there.

In the frequency converter according to the present invention, since the frequency dividing circuit is configured to output the frequency of the local oscillation signal and the mixed signal of the frequency-divided signal and the high-frequency signal, the number of circuits can be reduced, and the size can be reduced. This is effective for reducing power consumption.
Further, if a high-frequency transceiver is configured using the frequency converter of the present invention, the number of circuits constituting the high-frequency transceiver can be reduced, which is effective for miniaturization and low power consumption.

Embodiment 1 FIG.
FIG. 1 shows a frequency converter according to Embodiment 1 of the present invention. In FIG. 1, 1 is a power supply terminal, 2 is a high frequency (RF) signal input terminal, 3 is a local oscillation (LO) signal input terminal, 4 is a high frequency (RF) signal input circuit, 5 is an n divider circuit, and 6 is an output. A load 7 is an output signal terminal.

Hereinafter, operations and effects will be described. The frequency converter according to the first embodiment includes a high frequency (RF) signal having a frequency f ₁ input to a high frequency (RF) signal input circuit 4 via a high frequency (RF) signal input terminal 2 and a local oscillation (LO). ) The local oscillation (LO) signal having the frequency f ₂ input to the n frequency dividing circuit 5 through the signal input terminal 3 is mixed by the n frequency dividing circuit 5, and the frequency f ₁ ± (f ₂ / n) is mixed. A signal is taken out from the output signal terminal 7.

  In the frequency converter according to the first embodiment, a DC voltage is supplied from the power supply terminal 1 to the high frequency signal input circuit 4 and the n frequency dividing circuit 5 via the output load 6. In the conventional frequency converter, when the frequency of the local oscillator or PLL used for frequency mixing is higher than the desired LO signal frequency, a frequency divider is arranged in the previous stage of the frequency converter so that the desired frequency is obtained. After frequency division, the signal was input to the LO signal input section of the frequency converter as the LO signal. In the frequency converter according to the first embodiment, since the frequency dividing circuit is used as a part of the frequency converter, the number of circuits constituting the high-frequency transmitter / receiver can be reduced, which is effective for downsizing and low power consumption. .

Embodiment 2. FIG.
FIG. 2 shows a frequency converter according to the second embodiment of the present invention. The configuration and operation are basically the same as those in the first embodiment, but the RF signal input circuit 4 receives differential high frequency (RF) signals that are 180 degrees out of phase from the high frequency (RF) signal input terminals 2a and 2b. Similarly, the n frequency dividing circuit 5 also receives a differential LO signal having a phase difference of 180 degrees from the local oscillation (LO) signal input terminals 3a and 3b. Further, the n frequency dividing circuit 5 has a phase of 0, 90, and 180 at a frequency that is 1/2 of each differential LO signal that is 180 degrees different in phase from the local oscillation (LO) signal input terminals 3a and 3b. A signal divided by 270 degrees is generated and a differential high frequency (RF) signal having a phase difference of 180 degrees input from the RF signal input circuit 4 is mixed to obtain four different phases (0 degrees, 90 degrees, 180 degrees and 270 degrees) are output from the output terminals 7a to 7d.
The output load 6 is provided with four terminals 6a to 6d corresponding to the output terminals 7a to 7d.

  With such a configuration, the 90-degree distributor 35 that is conventionally required for the LO signal input section or the RF signal input section of the frequency converter becomes unnecessary, and the second frequency converters 29a and 29b are conventionally used. However, since only one of the n frequency divider circuits 5 is required, the size and power consumption can be reduced by further reducing the number of circuits.

Example 1.
FIG. 3 shows Example 1 of the radio frequency (RF) signal input circuit 4 in the second embodiment. In FIG. 3, the high frequency (RF) signal input circuit 4 is constituted by a pair of high frequency (RF) signal input transistors 12a and 12b. The power supply terminal 1, high-frequency signal input terminals 2a and 2b, local oscillation (LO) signal input terminals 3a and 3b, n frequency dividing circuit 5, output loads 6a to 6d, and output signal terminals 7a to 7d are shown in FIG. It is the same as that.

  Thereby, the frequency converter in Embodiment 2 can have a gain by applying an appropriate base bias to the transistor.

Example 2
Further, as shown in FIG. 4, by connecting the constant current sources 13a and 13b to the emitters of the high frequency (RF) signal input transistors 12a and 12b, it is possible to suppress the characteristic variation with respect to the variation of the elements constituting the frequency converter. it can. Here, bipolar transistors are used as the high-frequency (RF) input transistors 12a and 12b, but the same effect can be obtained by using a field effect transistor (FET).

Example 3 FIG.
Further, as shown in FIG. 5, by using high-frequency (RF) signal input resistors 14a and 14b instead of the high-frequency (RF) signal input transistors 12a and 12b, satisfactory saturation and distortion can be obtained as compared with the case where transistors are used. Characteristics can be obtained.

Example 4
Further, as shown in FIG. 6, by using high frequency (RF) signal input inductors 15a and 15b in place of the high frequency (RF) signal input transistors 12a and 12b, as compared with the case of using transistors as in the third embodiment. And good saturation / strain characteristics can be obtained.

Embodiment 3 FIG.
FIG. 7 shows a frequency converter according to Embodiment 3 of the present invention. In FIG. 7, 2a and 2b are radio frequency (RF) signal input terminals, 3a and 3b are local oscillation (LO) signal input terminals, 7a to 7b are output signal terminals, and 12a and 12b are radio frequency (RF) signal input circuits 4. The high-frequency (RF) signal input transistors 16 a and 16 b are D flip-flop circuits that constitute a divide-by-2 circuit as the n-divide-by circuit 5.

In the frequency converter according to the third embodiment, the n divider circuit 5 in the first embodiment of the second embodiment is a two-divider circuit composed of two D flip-flop circuits. A differential RF signal having a frequency f ₁ having a frequency f ₁ input to the high frequency (RF) signal input transistors 12a and 12b via the high frequency (RF) signal input terminals 2a and 2b, and a local oscillation (LO) signal A differential LO signal having a phase of 180 degrees and having a frequency f ₂ input to the frequency divider circuit 5 via the input terminals 3a and 3b is mixed, and four different phases (0 degree, 90 degrees, 180 degrees, signal of the frequency _{f 1 ± (f 2/2} ) having a 270 degrees) in which is taken out from the output signal terminal 7a to 7d.

  Although the D flip-flop circuits 16a and 16b are used in the third embodiment, the same effects as those of the third embodiment can be obtained even if other circuit configurations having a frequency dividing function are used.

Embodiment 4 FIG.
FIG. 8 shows a frequency converter according to the fourth embodiment of the present invention. Specific circuit examples of the D flip-flop circuits 16a and 16b constituting the divide-by-2 circuit 5 in the frequency converter according to the third embodiment. Is shown. In FIG. 8, 2a and 2b are high frequency (RF) signal input terminals, 3a and 3b are local oscillation (LO) signal input terminals, 7a to 7d are output signal terminals, and 12a and 12b are high frequency (RF) signal input circuits 4. A high-frequency (RF) signal input transistor, 16a and 16b are D flip-flop circuits composed of bipolar transistors, and 5 is a divide-by-2 circuit as an n-divider circuit consisting of the D flip-flop circuits 16a and 16b. A circuit 1 is a voltage source.

The D flip-flop circuit 16a includes switching transistors 20a to 20f and load resistors 21a and 21b, and the D flip-flop circuit 16b includes switching transistors 22a to 22f and load resistors 23a and 23b.
Further, the load resistors 21a, 21b and 23a, 23b have the functions of the output loads 66a to 6d shown in FIG.

  The operation will be described below. A divide-by-2 circuit using a general D flip-flop circuit is composed of the D flip-flop circuits 16a and 16b and the voltage source 1 in FIG. Each emitter is connected to a constant current source. Signals input from the clock terminal (terminal shown here as the LO terminal) of the D flip-flop circuit each have two different phases (0, 180 degrees), and the signal period is half of the input signal, that is, 1 Is output from the load resistors 21a, 21b and 23a, 23b as a frequency of / 2.

In the fourth embodiment, the collector terminal of the RF input transistor 12a is connected to the common emitter of the switching transistors 20a and 20b of the D flip-flop circuit 16a, and the switching transistors 22a and 22b of the D flip-flop circuit 16b are connected. The collector terminal of the RF input transistor 12b is connected to the common emitter.
Further, the LO signal from the input terminal 3b is inputted from the base terminals of the switching transistors 20a and 22a, and the phase of the LO signal from the input terminal 3a to the input terminal 3b is 180 degrees different from the base terminals of the switching transistors 20b and 22b. Input the LO signal.

  With this configuration, a D flip-flop circuit whose phase is divided into 0, 90, 180, and 270 degrees, respectively, at half the frequency of the LO signal input from the LO input signal terminals 3a and 3b. And the RF signal flowing through the collector terminal of the RF signal input transistor are mixed, and the mixed signal is output from the load resistors 21a, 21b and 23a, 23b to the output signal terminals 7a to 7d. It is.

  In the fourth embodiment, bipolar transistors are used as the switching transistor and the RF signal input transistor. However, a field effect transistor may be used. Further, the RF signal input transistor may be a resistor or an inductor as shown in Example 3 and Example 4 of the second embodiment.

  In the first to fourth embodiments, the example of the frequency converter used in the high frequency receiver has been described. However, the high frequency signal input circuit 4 is an intermediate frequency or baseband frequency input circuit, and a high frequency (RF) signal input is performed. Needless to say, by inputting an intermediate frequency or baseband frequency to the terminal 2, it can be used as a frequency converter for a transmitter.

Embodiment 5 FIG.
FIG. 9 shows a receiver according to Embodiment 5 of the present invention. In FIG. 9, 25 is an antenna, 26 is a low noise amplifier, 27 is a band pass filter, 30 is a low pass filter, 31 is a baseband amplifier, 32 is a decoder, 33 is a local oscillator, 34 is a frequency converter, and 36 is an output. Terminal.
Any one of the first to fourth embodiments is used for the frequency converter 34.

The operation will be described below. The reception (RF) signal received by the antenna 25 is amplified by the low noise amplifier 26, and then an unnecessary frequency is filtered by the band pass filter 27 and input to the frequency converter 34. On the other hand, the local oscillation (LO) signal output from the local oscillator 33 is input to the frequency converter 34, and is divided into two orthogonal signals of 0 degree and 90 degrees by the frequency converter 34, and this LO signal is received ( RF) signal and mixed to baseband signal. The converted baseband signal is input to the decoder 32 via the low pass filters 30a and 30b and the baseband amplifiers 31a and 31b, demodulated by the decoder 32, and output from the output terminal 36.
Output to.

  In addition, although the said Embodiment 5 demonstrated the receiver, this receiver can be used as a transmitter if the signal flow is reversed.

  In the frequency converter according to the present invention, the frequency divider circuit is configured to output the frequency of the local oscillation signal and a mixed signal of the frequency-divided signal and the high-frequency signal. If power can be achieved and it is applied to a transceiver of a mobile communication system, it is effective for downsizing and low power consumption of the transceiver.

It is a block diagram which shows Embodiment 1 of the frequency converter of this invention. It is a block diagram which shows Embodiment 2 of the frequency converter of this invention. 6 is a configuration diagram illustrating Example 1 of an RF signal input circuit 4 according to Embodiment 2. FIG. 6 is a configuration diagram illustrating Example 2 of the RF signal input circuit 4 according to Embodiment 2. FIG. 6 is a configuration diagram illustrating Example 3 of the RF signal input circuit 4 according to Embodiment 2. FIG. 6 is a configuration diagram illustrating Example 4 of the RF signal input circuit 4 according to Embodiment 2. FIG. It is a circuit diagram which shows the frequency converter in Embodiment 3 of this invention. It is a circuit diagram which shows the frequency converter in Embodiment 4 of this invention. It is a block diagram of the receiver in Embodiment 5 of this invention. It is a block diagram of the receiver using the conventional frequency converter.

Explanation of symbols

  1 power supply terminal, 2, 2a, 2b high frequency (RF) signal input terminal, 3, 3a, 3b local oscillation (LO) signal input terminal, 4 high frequency (RF) signal input circuit, 5 n frequency dividing circuit, 6, 6a to 6d output load, 7, 7a to 7d output signal terminal, 8a, 8b frequency converter, 9, 33 local oscillator, 100 degree distributor, 11 90 degree distributor, 12a, 12b RF signal input transistor, 16a, 16b D flip-flop circuit, 20a to 20f, 22a to 22f switching transistor, 21a, 21b, 23a, 23b load resistance, 25 antenna, 26 low noise amplifier, 27 band pass filter, 28 first frequency converter, 29 second Frequency converter, 30 low-pass filter, 31 baseband amplifier, 32 decoder.

Claims (6)

  An n frequency divider that divides an oscillation signal from a local oscillator and a high frequency signal input unit that inputs a high frequency signal are provided. The n frequency divider divides the input local oscillation signal to a frequency of 1 / n. And a frequency converter configured to input a high-frequency signal from the high-frequency signal input unit and output a mixed signal of the frequency component of the high-frequency signal and the 1 / n frequency.   The n frequency divider inputs a differential signal having a phase difference of 180 degrees as a local oscillation signal and a high-frequency signal, and a first output signal having a phase difference of an output signal as a reference phase, the first output signal And a fourth output signal having a phase difference of 90 degrees, a third output signal having a phase difference of 180 degrees, and a fourth signal having a phase difference of 270 degrees. The frequency converter according to 1.   3. The frequency converter according to claim 2, wherein a flip-flop circuit is used for the n frequency divider.   In the receiver which converts a received signal into a baseband signal by a frequency converter and demodulates by a decoder, the frequency converter according to any one of claims 1 to 3 is used as the frequency converter. Receiving machine.   4. The frequency converter according to claim 1, wherein the high-frequency signal input unit is an intermediate frequency or baseband frequency input unit, and is a transmitter frequency converter. 5.   In the transmitter that modulates a baseband signal with a modulator, converts it to a high-frequency signal with a frequency converter, and transmits it with an antenna, the frequency converter according to claim 5 is used as the frequency converter. Transmitter.

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