JP2002076974A - Receiving apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the frequency disturbance of a transmitting signal or a local oscillation signal at a time when a strong-input signal is received in the case of transmission without requiring a filter for eliminating an image in a receiving apparatus conducting transmission and reception by using radio waves. SOLUTION: The receiving apparatus has a receiving means 30 and a frequency synthesizer means 31 for selecting channels, the frequency synthesizer means has a voltage controlled oscillator and a frequency demultiplying means 1/N frequency-demultiplying (N> an integer of 1) an output from the voltage controlled oscillator, and the receiving means is supplied with a signal from the 1/N frequency demultiplying means as a local oscillation signal. Frequency close to that at a value obtained by adding or subtracting the quarter of a channel spacing A to or from the integral multiple of the channel spacing A is used as intermediate frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving apparatus for performing data communication using radio waves, and more particularly to a receiving apparatus which forms a home network at home.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional receiving apparatus of this type uses a surface acoustic wave filter (hereinafter referred to as SAW) as a receiving means.
A so-called single superheterodyne system using a mixer 2, mixer means 4, and ceramic filter 5 is used. A 400 MHz band radio wave which is a specific low power radio is considered as a transmission / reception signal. The 400 MHz band high frequency signal input to the antenna 1 is selectively amplified by the SAW filter 2 and the high frequency amplifying means 3 only in the vicinity of the desired signal. The selectively amplified signal is mixed by a mixer means 4 with a signal from a voltage controlled oscillation means (hereinafter referred to as VCO) 10. 450 KHz for ceramic filter 5
Signal is selectively taken out, and 450 KH
The signal z is amplified and demodulated by the demodulation means 7. Here, 450 KHz which is the output of the mixer means 4 is called an intermediate frequency signal.

[0003] In the mixer means 4, the frequency f1
As a result of mixing the signal of the VCO 10 and the signal from the high frequency amplifying means 3 having the frequency f2, the output of the mixer means 4 outputs the desired signal converted to 450 KHz and at the same time the image signal 900 KHz away from the desired signal. Is also converted to 450 KHz and output. However, there is no problem because the image signal is removed by the SAW filter 2.

At the time of transmission, the output of the VCO 10 is amplified by the transmission means 9, and then radio waves are radiated from the antenna 1 via the switching means 8.

[0005]

However, in the above-mentioned conventional receiving apparatus, in order to remove the image signal, the SAW is used.
A filter is needed. Further, even if a steep SAW filter is used, in order to remove an image signal, the limit of the intermediate frequency signal is about 450 KHz, and the intermediate frequency signal cannot be lowered. Therefore, it is difficult to employ an active filter as a filter for removing an adjacent channel in the intermediate frequency signal, and a ceramic filter is generally used.

Therefore, there are problems that (1) the shape of the receiving device becomes large, and (2) the receiving device becomes expensive.

Further, even if a low frequency can be used as the intermediate frequency signal, the frequency difference between the frequency of the local oscillation signal at the time of reception and the frequency of the desired reception signal becomes small, and the reception of a large input to the antenna 1 is reduced. When a signal is input, there is a problem that the oscillation frequency of the VCO 10 is pulled by the received signal and the frequency is disturbed. Therefore, there has been a problem that an accurate demodulation operation cannot be performed.

Further, at the time of transmission, a signal obtained by amplifying the oscillation signal of the VCO 10 is radiated from the antenna 1, and as a result, a part of the radiated energy returns to the VCO 10 to disturb the frequency or deteriorate the C / N. there were.

[0009]

According to the present invention, there is provided a receiving apparatus for receiving a predetermined signal B of a signal sequence assigned for each channel interval A on a frequency axis. It has a receiving means for receiving a predetermined signal B and a frequency synthesizer means for selecting a channel. The frequency synthesizer means divides a voltage controlled oscillator and an output of the voltage controlled oscillator by 1 / N (N> 1). integer)
A 1 / N frequency dividing means for supplying a signal from the 1 / N frequency dividing means to the receiving means as a local oscillation signal. A frequency obtained by adding or subtracting / 4 is defined as an intermediate frequency which is a frequency of a difference between the predetermined signal B and the local oscillation signal.

According to the above invention, the local oscillation signal is V
Since a signal having a frequency 1 / N times that of CO is used, the frequency of the local oscillation signal is not disturbed even when a large input reception signal is input. Further, since the image frequency is arranged between the channels, there is no large interference signal near the image frequency, and the image interference characteristic can be easily improved without using a SAW filter.

[0011]

The receiving apparatus according to claim 1 of the present invention is a receiving apparatus for receiving a predetermined signal B of a signal sequence assigned for each channel interval A on a frequency axis, Having a receiving means for receiving the predetermined signal B and a frequency synthesizer means for performing channel selection,
The frequency synthesizer means includes a voltage controlled oscillator and 1 / N frequency dividing means for dividing the output of the voltage controlled oscillator by 1 / N (N> 1 integer). It is configured to be supplied to the receiving means as a local oscillation signal,
In addition, a frequency obtained by adding or subtracting 1/4 of the channel interval A to an integral multiple of the channel interval A is set as an intermediate frequency which is a frequency of a difference between the predetermined signal B and the local oscillation signal. .

Then, as a local oscillation signal, 1 / VCO
Since a signal having N times the frequency is used, the frequency of the local oscillation signal is not disturbed even when a large input reception signal is input. Further, since the image frequency is arranged between the channels, there is no large interference signal near the image frequency, and the image interference characteristic can be easily improved without using a SAW filter.

According to a second aspect of the present invention, there is provided a receiving apparatus for receiving a predetermined signal B in a signal sequence assigned for each channel interval A on a frequency axis, wherein the predetermined signal B And frequency synthesizer means for selecting a channel, the frequency synthesizer means having a voltage controlled oscillator and N multiplying means for multiplying the output of the voltage controlled oscillator by N, and the N multiplying means. And a signal having a value obtained by adding or subtracting 1/4 of the channel interval A to an integral multiple of the channel interval A is defined as the predetermined signal B. An intermediate frequency which is a frequency of a difference between the local oscillation signals is used.

Since a signal having a frequency multiplied by N of the VCO is used as the local oscillation signal, the frequency of the local oscillation signal is not disturbed even if a large input reception signal is input. Further, since the image frequency is arranged between the channels, there is no large interference signal near the image frequency, and the image interference characteristic can be easily improved without using a SAW filter.

According to a third aspect of the present invention, the frequency conversion means for converting the reception signal of the receiving apparatus into an intermediate frequency signal includes an I signal which is an output obtained by multiplying the reception signal by two orthogonal local oscillation signals. The image frequency is canceled by using two signals of the Q signal.

The image signal can be canceled by using the I signal and the Q signal, so that the image interference characteristic can be easily improved.

The reference signal for generating the local oscillation frequency of the receiving apparatus according to claim 4 of the present invention is a signal obtained by dividing the signal of the crystal oscillator by 1 / M, and the frequency of the reference signal is set to a channel interval A. The oscillation frequency of the crystal oscillator is set so as to be deviated from the value by a predetermined frequency.

Since the local oscillation frequency is an integral multiple of the reference frequency, which is a value shifted from the value of the channel interval A by a predetermined frequency, the predetermined local oscillation frequency can be easily created.

The reference frequency of the receiving apparatus according to claim 5 of the present invention is a frequency obtained by dividing the frequency oscillated by the crystal oscillator, and a switching means for switching the oscillation frequency of the crystal oscillator between transmission and reception. In transmission, the reference frequency is set near the value of the channel interval A, and during reception, the reference frequency is set to a value shifted from the value of the channel interval A by a predetermined frequency.

Since a predetermined local oscillation frequency can be created at the time of transmission and at the time of reception, respectively, the transmission signal generation means at the time of transmission and the local oscillation signal creation means at the time of reception can be shared by the same configuration. This has the effect of simplifying the circuit configuration.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a receiving apparatus according to Embodiment 1 of the present invention.

In FIG. 1, 1 is an antenna, 3 is a high frequency amplifying means, 20 is a frequency converting means, 25 is an adding means,
6 is a filter, 6 is an amplifying means, 7 is a demodulating means, 8 is a switching means, 9 is a transmitting means for amplifying and outputting a high frequency signal,
10 is a VCO, 51 is a １ ／ frequency divider, 11 is a first frequency divider, 12 is a phase comparator, 13 is a second frequency divider,
14 is a crystal oscillator, 15 is a loop filter, and 27 is a quadrature signal generating means. The frequency conversion means 20 includes a first mixer means 21, a first phase shift means 22, a second mixer means 23, and a second phase shift means 24. The crystal oscillator has a crystal 16, a capacitor 17, a capacitor 18, an electronic switch 28, and a capacitor 29. Reference numeral 30 denotes a receiving unit for receiving a high-frequency signal, and reference numeral 31 denotes a frequency synthesizer for performing channel selection.

Next, the operation and operation will be described. First, as a desired signal (meaning a predetermined signal B shown in the claims), 4
A case where a specific low-power radio wave in the 00 MHz band is received will be described. In the case of 400MHz specific low power radio,
Signals are allocated at 12.5 KHz intervals. That is, the frequency interval A is A = 12.5 KHz. The radio wave of the signal train with a frequency interval of 12.5 KHz
To enter. The radio wave input to the antenna 1 is applied by the switching means 8 to the high frequency amplification means 3. After the radio wave in the 400 MHz band is amplified by the high frequency amplifying means 3, it is input to the frequency converting means 20. The frequency conversion means 20 is an image canceling mixer, and is configured to cancel an image signal. The local oscillation signal from the 分 frequency dividing means 51 is divided into two orthogonal signals by the orthogonal signal generating means 27, and is applied to the first mixer means 21 and the second mixer means 23. The output of the first mixer means 21 and the output of the second mixer means 23 are orthogonal outputs.
The outputs of the first mixer means 21 and the second mixer means 23 are called intermediate frequency signals.

More specifically, when the frequency of the signal input to the antenna 1 is higher than that of the local oscillation signal, the phase of the output of the first mixer 21 is higher than that of the second mixer 23. Is advanced by 90 degrees, and when the frequency of the signal input to the antenna 1 is lower than that of the local oscillation signal, the output of the first mixer
The phase is delayed by 90 degrees from the output of the mixer means 23. Here, if the local oscillation signal is selected to have a lower frequency than the desired signal, when the desired signal is input to the antenna 1, the output of the first mixer means 21 is output to the second mixer means 23.
In the case of an image signal, the phase of the output of the first mixer means 21 lags the phase of the output of the second mixer means 90 by 90 degrees. These two signals are respectively applied to the first phase shifting means 22.
Then, it is input to the phase shifting means 24. The first phase shifting means 22 delays the signal by 45 degrees, and the second phase shifting means 24 advances the signal by 45 degrees. As a result, the phase relationship between the output of the first phase shifting means 22 and the output of the second phase shifting means 24 becomes the same phase in the case of the desired signal, and becomes the opposite phase in the case of the image signal. Therefore, as a result of the addition of the two signals by the adding means 25, the desired signal is output twice, and the image signal is canceled. Then, the adjacent channel signal is removed by the filter 26. The desired signal is amplified by the amplifying means 6 and demodulated by the demodulating means 7.

Next, a method for creating a local oscillation signal will be described. The signal oscillated by the VCO 10 is divided by a 1/2 frequency dividing means 51.
, And the first frequency dividing means 11 divides the frequency by 1 / N. On the other hand, the signal oscillated by the crystal oscillator 14 is the second
Of the phase comparator 12
Becomes a reference signal near 12.5 KHz. The phase comparator 12 detects the phase error between the reference signal near 12.5 KHz and the signal obtained by dividing the frequency of the VCO signal by 1 / (2 × N), and outputs the VCO signal through the loop filter 15 in a direction in which the phase error becomes zero. Control the oscillation frequency and phase of the Therefore, the oscillation frequency of the VCO is 2 × N times the reference signal. Therefore, the local oscillation signal fl which is the output of the 1/2 frequency dividing means 51 becomes N times the reference signal. Here, by varying N, the oscillation frequency of the local oscillation signal fl can be varied in reference signal frequency steps. According to the configuration of the present embodiment,
VCO even if a large input signal is input to the antenna
The oscillation frequency of the VCO 10 does not disturb the oscillation frequency of the VCO 10.

Next, consider the time of transmission. At the time of transmission, the output signal of the 分 frequency divider 51 is amplified by the transmitter 9 and radiated from the antenna 1 via the switch 8. The desired transmission frequency can be obtained by changing the frequency division number N of the first frequency dividing means 11 for the transmission signal frequency. That is, any radio wave of a signal train with a channel interval of 12.5 KHz can be radiated. In the case of the FM modulation, both the oscillation frequency of the VCO 10 and the oscillation frequency of the crystal oscillator 14 are modulated. However, the modulation is adjusted so that the modulation at the output of the 1/2 frequency dividing means 51 becomes a specified modulation. There is a need to. According to the configuration of the present embodiment, even if a part of the energy radiated from the antenna 1 returns to the VCO 10, the oscillation frequency of the VCO 10 is greatly different from that of the VCO 10,
The oscillation frequency of the VCO 10 is not disturbed.

Now, the crystal oscillator 14 has the electronic switch 2
The oscillation frequency can be varied by turning ON / OFF 8. At the time of transmission, the electronic switch 28 is turned off. The oscillation frequency of the crystal oscillator 14 is adjusted so that the reference signal frequency input to the phase comparator 12 when the electronic switch 28 is OFF is 12.5 KHz.
Therefore, at the time of transmission, an integer multiple of 12.5 KHz is radiated from the antenna 1 as a radio wave. That is, any radio wave of a signal train with a channel interval of 12.5 KHz can be radiated. At the time of transmission, the switching means 8 sets the electronic switch 2
8 is connected to the transmitting means 9 side in conjunction with the switching of 8. At the time of reception, the electronic switch 28 is turned on, and the capacitor 29 is added in parallel with the capacitor 17. Therefore, the oscillation frequency of the crystal oscillator 14 is shifted slightly lower. And the first
By setting the frequency dividing number of the frequency dividing means 11 to the frequency dividing number for producing the local oscillation frequency, the signal frequency of the 1/2 frequency dividing means 51, that is, the local oscillation frequency fl becomes fl = (12.5−Δf ) N = (12.5 × N−Δf ×)
N) KHz. On the other hand, the desired signal fo to be received is fo = 12.5 × KKHz (K is an integer).

The intermediate frequency signal fm is fm = fo−fl = 12.5 × (K−N) −Δf × NKH
z.

Here, selection is made so that Δf × N = 12.5 KHz / 4. Next, consider an image signal. The image signal fi is fi = fo−2 × fm = 12.5 × (2 × NK) −2
× Δf × N = 12.5 × (2 × NK) −12.5 / 2 KHz. That is, the image signal fi has a channel interval of 1
The frequency becomes an intermediate frequency of the signal train of 2.5 KHz. Therefore, no signal is arranged in the vicinity of the image signal, and only the energy component out of the band of the signal train causes image disturbance. Since the energy at the edge of the band is not so large, the image disturbance is not so large. Further, as described above, the image canceling type frequency converting means 20 is used.
, The image disturbance is further reduced.

According to the first embodiment, since no filter such as a SAW filter is required in the high frequency amplification stage for removing the image frequency, it is not necessary to select an intermediate frequency in a region where the SAW filter attenuates sufficiently. Therefore, the intermediate frequency is selected to be a low frequency such as 46.875 KHz. The filter 26 is constituted by a filter using a semiconductor integrated circuit such as a switched capacitor filter and an active filter.

When the receiving channel is changed by changing the frequency dividing number N of the first frequency dividing means 11, since Δf does not change even if the channel is changed, Δf of the image signal is 12.5 KHz.
Is slightly deviated from 12.5 KHz / 2, but the deviation is very small and does not pose a problem in a normal receiving apparatus.

Although the adding means 25 is used, a subtracting means can be used depending on the phase relationship between the first phase shifting means 22 and the second phase shifting means 24.

(Embodiment 2) FIG. 2 is a block diagram showing a communication apparatus according to Embodiment 2 of the present invention.

In the second embodiment, FIG.
The same numbers are assigned to the same functional blocks as in the block diagram shown in FIG. The difference from the first embodiment shown in FIG.
In this embodiment, a doubling means 52 is used in place of the 1/2 frequency dividing means 51 in FIG. By using the doubling means 52, control is performed so that 2 / N times the oscillation frequency of the VCO 10 becomes equal to the reference signal frequency. Therefore, the local oscillation frequency or transmission frequency is VCO1
Since it is twice the oscillation frequency of 0, it is controlled to be N times the reference signal frequency. Local oscillation frequency or transmission frequency is 40
Since the signal is in the 0 MHz band, the oscillation frequency of the VCO 10 is in the 200 MHz band. According to the configuration of this embodiment, as in the case of the first embodiment, even when a large input signal is input to the antenna, the oscillation frequency of the VCO 10 is greatly different from the oscillation frequency of the VCO 10 and disturbs the oscillation frequency of the VCO 10. Never. Also, even when a part of the energy radiated from the antenna 1 returns to the VCO 10 at the time of transmission, the oscillation frequency of the VCO 10 is greatly different from that of the VCO 10.
It does not disturb the oscillation frequency of O10.

(Embodiment 3) FIG. 3 is a block diagram showing another embodiment of the frequency conversion means 20 which can be used in the receiving apparatus according to the first or second embodiment of the present invention.

In the third embodiment, 21 is a first mixer, 23 is a second mixer, 31 is a first band-pass filter, 32 is a third mixer, and 33 is a second band-pass filter. , 34 are fourth mixer means,
25 is an adding means.

Next, the operation and operation will be described. The signal from the high frequency amplifying means 3 is input to the first mixer means 21 and the second mixer means 23, and is multiplied by orthogonal local transmission signals fl1 and fl2, respectively. The intermediate frequency signals fm1 and fm2 orthogonal to each other are output to the outputs of the first mixer means 21 and the second mixer means 23, respectively.

After the intermediate frequency signals fm1 and fm2 have their unnecessary signals removed by the first band-pass filter 31 or the second band-pass filter 33, respectively.
Third mixer means 32 or fourth mixer means 3
4 is multiplied by the second local oscillation signals fa1 and fa2 which are orthogonal to each other. fa1 and fa2 are orthogonal to each other. Next, the outputs of the third mixer means 32 and the fourth mixer means 34 are added by the addition means 25. As a result, the image signal is canceled. Here, for example, fm1 and fm2
Selected 46.875 KHz, and set fa1 and fa2 to 37.875 kHz.
If 5 KHz is selected, the output of the adding means 25 will be 9.375 KHz. Then, although not shown in FIG. 3, adjacent channels are removed by a band-pass filter having a center frequency of 9.375 KHz provided at the subsequent stage of the adding means 25. The circuit shown in the third embodiment shows another configuration method of the frequency conversion means 20 in the first or second embodiment. With the configuration of the third embodiment, an image signal can be accurately removed over a wide frequency range.

[0040]

As described above, the receiving apparatus according to the first aspect of the present invention is a receiving apparatus for receiving a predetermined signal of a signal sequence assigned for each channel interval A on the frequency axis. Receiving means and frequency synthesizer means for performing channel selection, the frequency synthesizer means comprising a voltage controlled oscillator, a frequency dividing means for dividing the oscillation output of the voltage controlled oscillator, and an output of the variable frequency dividing means. Phase comparison means for detecting a phase error with the reference signal,
A signal obtained by dividing the output of the voltage-controlled oscillator by 1 / N (an integer of N> 1) is supplied to the receiving means as a local oscillation signal, and one of the channel interval A is set to an integral multiple of the channel interval A. Since the vicinity of the frequency at which the value of / 4 is added or subtracted is set as the intermediate frequency, the desired signal and the oscillation frequency of the VCO are separated by about N times, so that even if a large input reception signal is input, the local oscillation signal There is an effect that the frequency is not disturbed. Furthermore, since the image frequency is located between the channels, there is no large interference signal near the image frequency, and the image interference characteristics can be easily improved without providing a SAW filter for removing the image in the high frequency amplification stage. There is an effect that can be.

According to a second aspect of the present invention, there is provided a receiving apparatus for receiving a predetermined signal in a signal sequence assigned for each channel interval A on the frequency axis, and for performing channel selection with the receiving means. Frequency synthesizer means, wherein the frequency synthesizer means detects a phase error between a voltage controlled oscillator, a frequency dividing means for dividing the oscillation output of the voltage controlled oscillator, an output of the variable frequency dividing means, and a reference signal. A phase comparison means, wherein a signal obtained by multiplying the output of the voltage controlled oscillator by N (N> 1) is supplied to the receiving means as a local oscillation signal. Since the vicinity of the frequency at which 1/4 of the channel interval A is added or subtracted is set as the intermediate frequency, the desired signal and the oscillation frequency of the VCO are approximately N
Since the distance is twice, there is an effect that the frequency of the local oscillation signal is not disturbed even if a large input reception signal is input. Furthermore, since the image frequency is located between the channels, there is no large interference signal near the image frequency, and the image interference characteristics can be easily improved without providing a SAW filter for removing the image in the high frequency amplification stage. There is an effect that can be.

The frequency conversion means for converting the reception signal of the receiving apparatus into an intermediate frequency signal is an I signal and a Q signal which are outputs obtained by multiplying the reception signal by two orthogonal local oscillation signals. Since the image frequency is canceled by using the two signals, the image signal can be canceled by using the I signal and the Q signal, and the image signal can be more accurately removed.

The reference signal for generating the local oscillation frequency of the receiving apparatus according to claim 4 is a signal obtained by dividing the signal of the crystal oscillator by 1 / M, and the frequency of the reference signal is set to the value of the channel interval A. Since the oscillation frequency of the crystal oscillator is set so as to be shifted from the predetermined value by a predetermined frequency, there is an effect that a predetermined local oscillation frequency can be easily created.

The reference frequency of the receiver according to claim 5 is a frequency obtained by dividing the frequency oscillated by the crystal oscillator, and has switching means for switching the oscillation frequency of the crystal oscillator between transmission and reception. Since the reference frequency is set near the value of the channel interval A at the time of transmission, and the reference frequency is set to a value shifted from the value of the channel interval A by a predetermined frequency at the time of reception. It is possible to share the local transmission signal generating means at the time of reception with the same configuration, which has the effect of simplifying the circuit configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram of a receiving apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a receiving device according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a frequency conversion unit of the receiving apparatus according to the first or second embodiment of the present invention.

FIG. 4 is a block diagram of a conventional receiving apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 SAW filter 3 High frequency amplification means 4 Mixer means 8 Switching means 9 Transmission means 10 Voltage control oscillation means (VCO) 11 First frequency dividing means 12 Phase comparing means 13 Second frequency dividing means 14 Crystal oscillator 15 Loop filter Reference Signs List 16 crystal oscillator 20 frequency conversion means 21 first mixer means 22 first phase shifting means 23 second mixer means 24 second phase shifting means 25 adding means 26 filter 27 orthogonal signal generating means 28 electronic switch 30 receiving means 31 frequency synthesizer means 51 1/2 frequency dividing means 52 doubler means

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K004 AA05 FA01 FH01 FK06 5K011 DA06 DA08 DA21 FA01 GA04 KA08 KA13 5K020 AA03 DD02 DD11 DD22 FF01 FF02 GG04 GG11 KK00 KK07 MM04 5K022 AA10 AA28

Claims (5)

[Claims] 1. A receiving apparatus for receiving a predetermined signal B of a signal sequence assigned for each channel interval A on a frequency axis, wherein the receiving apparatus receives the predetermined signal B and performs channel selection. Frequency synthesizing means, comprising: a voltage controlled oscillator; and a 1 / N frequency dividing means for dividing the output of the voltage controlled oscillator by 1 / N (N> 1 integer). A signal from the 1 / N frequency dividing means is supplied to the receiving means as a local oscillation signal, and a frequency which is a value obtained by adding or subtracting 1/4 of the channel interval A to an integral multiple of the channel interval A is used. A receiving device, wherein the intermediate frequency is a frequency of a difference between the predetermined signal B and the local oscillation signal. 2. A receiving apparatus for receiving a predetermined signal B of a signal sequence allocated for each channel interval A on a frequency axis, wherein the receiving apparatus receives the predetermined signal B and performs channel selection. Frequency synthesizing means, the frequency synthesizing means having a voltage controlled oscillator and N multiplying means for multiplying the output of the voltage controlled oscillator by N, and receiving a signal from the N multiplying means as a local oscillation signal. And a frequency obtained by adding or subtracting 1/4 of the channel interval A to an integral multiple of the channel interval A is a frequency of a difference between the predetermined signal B and the local oscillation signal. A receiving device having an intermediate frequency. 3. A frequency conversion means for converting a reception signal into an intermediate frequency signal, wherein two signals of an I signal and a Q signal which are outputs obtained by multiplying the reception signal by two orthogonal local oscillation signals are provided. 3. The receiving apparatus according to claim 1, wherein the receiving apparatus is configured to cancel the image frequency by using the receiving apparatus. 4. A crystal oscillator for generating a reference signal, wherein the reference signal is a signal obtained by dividing a signal of the crystal oscillator by 1 / M. 4. The receiving device according to claim 1, wherein the oscillation frequency of the crystal oscillator is set so as to have a value shifted by only one. 5. The reference frequency is a frequency obtained by dividing a frequency oscillated by a crystal oscillator, and has switching means for switching the oscillation frequency of the crystal oscillator between transmission and reception. 5. The system according to claim 4, wherein the reference frequency is set to a value shifted from the value of the channel interval A by a predetermined frequency during reception.
The receiving device according to the above.