JP2002280924A - Multi-band transceiver - Google Patents

Abstract

(57) [Problem] To provide a multi-band transmission / reception device capable of reducing the number of required local oscillators, reducing the size, weight, power consumption, and cost of the device. SOLUTION: A first frequency divider to which an output of a first local oscillator is inputted, a second frequency divider to which an output of a second local oscillator is inputted, and a radio frequency reception signal are inputted. A down-converter that outputs a reception intermediate frequency signal, an up-converter that receives a transmission intermediate frequency signal and outputs a radio frequency transmission signal, and a down-converter that outputs the output of the first frequency divider and the output of the second frequency divider And a switch for switching and inputting to a local oscillation signal input terminal of the up-converter and a local oscillation signal input terminal of the up-converter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-band transmitting / receiving apparatus usable for a plurality of radio communication systems.

[0002]

2. Description of the Related Art Wireless communication systems include an FDD system in which transmission signals and reception signals use different frequencies, and a TDD system in which transmission signals and reception signals are separated by time. Conventional FDD
FIG. 6 shows a transmitting / receiving device for the system. In FIG. 6, 1 is an antenna, 2 is an antenna duplexer, 3 is a low noise amplifier, 4
Is a down-converter, 5 is a radio frequency (RF) local oscillator, 6 is a band pass filter, 7 is an intermediate frequency (IF) receiving local oscillator, 8 is a π / 2 phase shifter, 9 and 10 are mixers, 11 , 12 are low-pass filters, 13, 14 are AD
Converter, 15 is a baseband processing circuit, 16 and 17 are D
A converter, 18 and 19 are low-pass filters, 25 is IF
, A π / 2 phase shifter, 21 and 22
Is a mixer, 23 is an adder, 24 is a bandpass filter,
26 is an up-converter and 27 is a high-output amplifier.

A signal received by an antenna 1 is split by an antenna duplexer 2 and input to a low noise amplifier 3 where it is amplified. Next, it is converted into a reception IF signal by the down converter 4 and the local oscillator 5 of RF. As the local oscillator 5, a frequency synthesizer whose output frequency is variable is generally used. After a signal of a desired channel is extracted from the received IF signal by the band-pass filter 6, the IF receiving local oscillator 7, the π / 2 phase shifter 8, the mixers 9, 10
, And is converted to a reception baseband signal. This received baseband signal is applied to a low-pass filter 11.
After being input to the AD converters 13 and 14 via the and 12 and converted into digital signals, they are input to the baseband processing circuit 15.

On the other hand, the transmission baseband signal output from the baseband processing circuit 15 is applied to DA converters 16 and 1.
After being converted into an analog signal by 7, the band is limited by low-pass filters 11 and 12. Next, the mixers 21 and 22, the IF local oscillator 25, π / 2
Quadrature modulated by the phase shifter 20 and the adder 23, and the transmission I
It is converted to an F signal. The transmission IF signal passes through a band-pass filter 24 and is converted into a transmission RF signal by an RF local oscillator 25 and an up-converter 26. The signal is further amplified by the high-power amplifier 27 and transmitted from the antenna 1 through the antenna duplexer 2.

[0005] Since the reception IF frequency and the transmission IF frequency differ only by the difference between the reception RF frequency and the transmission RF frequency, I IF
Two local oscillators of F are required. Ratio (variable bandwidth) between the variable frequency bandwidth of the voltage controlled oscillator (VCO) used for such a local oscillator and the center frequency of the variable frequency range
Is usually about 10%, so that a local oscillator corresponding to each band is required in order to configure a transmission / reception apparatus corresponding to a multi-band wireless system exceeding this. When the number of bands is N, the local oscillator of RF is N
Are required, and these are switched by a switch. If the transmission IF frequency is common to the multi-bands, the number of IF local oscillators is one, but the reception RF frequency and transmission R
Since the difference between the F frequencies differs from system to system, N local oscillators for reception of IF are required, and these are switched by a switch.

In a transmission / reception apparatus of the FDD system, reception I
The F frequency and the transmission IF frequency can be common, and the number of IF local oscillators can be one. However, in this case, two RF local oscillators that differ by the RF frequency difference between transmission and reception are required. To be provided. In this case, when the number of bands is N, 2 × N RF local oscillators are required, and these are switched by a switch. The IF has one local oscillator. FIG. 7 shows a conventional transmitting / receiving apparatus for the TDD system. In this figure, the same parts as those in FIG. 6 are given the same numbers. Since the transmitting and receiving RF frequencies are the same in the TDD system, the local oscillator of the IF may be one of the local oscillators 7. In this case, when the number of bands is M, RF
Need M local oscillators, and these are switched by a switch. The IF has one local oscillator.

Therefore, in order to configure a transmitting / receiving apparatus compatible with the FDD system with N bands and the TDD system with M bands, N + M RF local oscillators are required.
These are switched by a switch. At this time, assuming that the transmission IF is common and the transmission local oscillator is one, TD
In the case of the D system, the local oscillator for transmission of the IF is used as it is as the local oscillator for reception, and in the case of the FDD system, the local oscillator for reception of N IFs is prepared and switched by a switch. N + 1.

[0008] Alternatively, the transmission and reception IF
And the RF local oscillator is 2 × N +
Prepare M and switch with the switch.

Taking a specific wireless system as an example, the corresponding radio frequency bands are as follows. 1. PDC800M: FDD system, reception frequency 810
1.-885 MHz, transmission frequency 898-956 MHz PDC1.5G: FDD system, reception frequency 147
7 ~ 1501MHz, transmission frequency 1429-1453M
Hz 3. PHS: TDD system, transmission / reception frequency 1895.1
5 to 1917.95 MHz 4.2.4 GHz wireless LAN: TDD system, transmission / reception frequency 2402 to 2484 MHz 5.5 GHz wireless LAN: TDD system, transmission / reception frequency 5170 to 5230 MHz

In this case, the required number of local oscillators is R
F5 and IF3, or RF7 and IF1.

[0011] When there are two types of radio frequency bands to cope with, various measures have been taken to reduce the number of local oscillators. Japanese Patent Application Laid-Open No. 2000-115013 discloses RF
Is set as the center frequency between two radio frequency bands, and the local oscillator of IF is set as the difference between the center frequency and the high frequency band, so that the number of local oscillators is one RF,
There is one IF. However, the FDD method requires one more local oscillator for generating a frequency corresponding to the frequency difference between transmission and reception. In Japanese Patent Laid-Open No. Hei 10-145262, a fundamental wave of a VCO is used in one radio frequency band, and a harmonic of the VCO is used in another radio frequency band.

[0012]

In the conventional transmitting and receiving apparatus as described above, the number of local oscillators increases as the number of corresponding radio frequency bands increases more than two. The local oscillator is composed of a large number of components, such as a loop filter and a PLL IC combining discrete resistors and capacitors, in addition to the above-described voltage-controlled oscillator. There is a problem that it is difficult to reduce the cost and cost.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a multi-band transmitting / receiving apparatus in which the number of local oscillators is reduced as much as possible.

[0014]

According to one aspect of the present invention, there is provided a multi-band transmitting / receiving apparatus comprising: a first local oscillator; a second local oscillator; and a first local oscillator. A first frequency dividing means to which an output is input, the frequency dividing ratio being variable; a second frequency dividing means to which an output of the second local oscillator is inputted, the variable frequency dividing ratio; A quadrature demodulator to which a reception signal is input and outputs a reception baseband signal; a quadrature modulator to which a transmission baseband signal is input and outputs a radio frequency transmission signal;
A switch for switching and inputting the output of the frequency dividing means and the output of the second frequency dividing means to a local oscillation signal input terminal of the quadrature demodulator and a local oscillation signal input terminal of the quadrature modulator, The reception intermediate frequency and the transmission intermediate frequency are the same, and in the FDD system, the output of the first frequency divider is connected to the local oscillation signal input terminal of the quadrature demodulator or the local oscillation signal input terminal of the quadrature modulator. The output of the second frequency divider is output from the first frequency divider among the local oscillation signal input terminal of the quadrature demodulator and the local oscillation signal input terminal of the quadrature modulator. An input terminal that is not input is input via the switch, and in the TDD system, one of the output of the first frequency divider and the output of the second frequency divider is output to the quadrature demodulator. Parts input to the oscillation signal input terminal and the local oscillation signal input terminal of the quadrature modulator.

In another multi-band transmitting / receiving apparatus according to the present invention, a first local oscillator, a second local oscillator, and an output of the first local oscillator are inputted, and the frequency division ratio is variable. 1 frequency dividing means, a second frequency dividing means to which an output of the second local oscillator is input, and a variable frequency dividing ratio;
A quadrature demodulator that receives a radio frequency reception signal and outputs a reception baseband signal; a quadrature modulator that receives a transmission baseband signal and outputs a radio frequency transmission signal; A switch for switching and outputting an output and an output of the second frequency dividing means to a local oscillation signal input terminal of the quadrature demodulator and a local oscillation signal input terminal of the quadrature modulator; 1 is input to the local oscillation signal input terminal of the quadrature demodulator or the local oscillation signal input terminal of the quadrature modulator via the switch, and the output of the second frequency dividing means is input to the quadrature demodulator. Inputting, via the switch, an input terminal of a local oscillation signal input terminal of the demodulator and a local oscillation signal input terminal of the quadrature modulator to which the output of the first frequency dividing means is not input. In the TDD system, one of the output of the first frequency dividing means and the output of the second frequency dividing means is used as a local oscillation signal input terminal of the quadrature demodulator and a local oscillation signal input terminal of the quadrature modulator. To enter.

In this way, the local oscillator of RF becomes 2
A single or zero IF local oscillator can be used to configure a multi-band transmitting / receiving device that performs communication in a plurality of radio frequency bands, so that the device can be reduced in size, weight, power consumption, and cost. Becomes

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a diagram showing a configuration of a multi-band transmitting / receiving apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is an antenna, 2 is an antenna duplexer, 3 is a low noise amplifier, 4 is a down converter, 6 is a bandpass filter, 7 is a local oscillator of IF,
8 is a π / 2 phase shifter, 9 and 10 are mixers, 11 and 12 are low-pass filters, 13 and 14 are AD converters, 15 is a baseband processing circuit, 16 and 17 are DA converters, 18, 1
9 is a low-pass filter, 20 is a π / 2 phase shifter, 21, 2
2 is a mixer, 23 is an adder, 24 is a bandpass filter, 26 is an upconverter, 27 is a high-power amplifier, 3
0 is the first RF local oscillator, 31 is the second RF local oscillator, 32 is the first frequency dividing means, 33 is the second frequency dividing means, 3
4 is a first switch, 35 is a second switch, 36 is a third switch, and 37 is a fourth switch.

In the transmitting / receiving apparatus of this embodiment, the IF frequency of the transmitting and receiving circuits is common, the local oscillator of the IF is one of the local oscillators 7, and the local oscillator of the RF is the first RF local oscillator 30 and the local oscillator of the RF. Two second RF local oscillators 31 are used, and each divided signal is switched by a switch and input to the up-converter 26 or the down-converter 4.

In the FDD system, two RF local oscillators are used together, and in the TDD system, one of the two RF local oscillators is used.

In the following, description will be given taking the above-mentioned wireless system as an example. The corresponding radio frequency bands are as follows. 1. PDC800M: FDD system, reception frequency 810
1.-885 MHz, transmission frequency 898-956 MHz PDC1.5G: FDD system, reception frequency 147
7 ~ 1501MHz, transmission frequency 1429-1453M
Hz 3. PHS: TDD system, transmission and reception frequency 1895.15
１９1917.95 MHz 4. 2.4 GHz wireless LAN: TDD system, transmission / reception frequency 2402 to 2484 MHz 5GHz wireless LAN: TDD system, transmission / reception frequency 5170-5230MHz

On the other hand, the IF of the transmitting and receiving circuit
The frequency is fixed at 200 MHz, and the local oscillator of the IF is one of the local oscillators 7 outputting 200 MHz.
The variable frequency range of the first RF local oscillator 30 is set to 50
50 to 5530 MHz (9% relative bandwidth), the variable frequency range of the second RF local oscillator 31 is 3490 to 3780 MHz
z (fractional bandwidth 8%).

In the PDC 800M, the first switch 34
And the third switch 36, and the second switch 35 and the fourth switch 37. Also the first R
First frequency dividing means 32 connected to F local oscillator 30
Is set to 5, the output of the first frequency dividing means 32 becomes 1010 to 1106 MHz and is input to the down converter 4. Therefore, the reception frequency is 810 to 885 MH
The signal of z can be converted into a reception IF signal of 200 MHz.
On the other hand, the second RF local oscillator 31 connected to the second
By setting the frequency dividing number of the frequency dividing means to 5, the output of the second frequency dividing means becomes 698 to 756 MHz and is input to the up-converter 26. Therefore, a 200 MHz transmission IF signal can be converted to a transmission frequency of 898 to 956 MHz.

In PDC1.5G, the connection of the switch is P
Same as DC800M. First RF local oscillator 30
Is set to 4, the output of the first frequency dividing means 32 is 1262.5 to 1262.5.
It becomes 1382.5 MHz and is input to the down converter 4. Therefore, a signal with a reception frequency of 1477 to 1501 MHz can be converted into a reception IF signal of 200 MHz. On the other hand, by setting the frequency division number of the second frequency dividing means connected to the second RF local oscillator 31 to 3, the output of the second frequency dividing means becomes 1163 to 1260 MHz, Is entered. Therefore, 200MHz transmission IF
The signal can be converted to a transmission frequency of 1429-1453 MHz.

In the PHS, the connection between the first switch 34 and the third switch 36 and the connection between the first switch 34 and the fourth switch 37 are switched according to transmission and reception times.
This connection is shown in FIG. In this drawing, the thin line and the thick line of the first switch 34 indicate that they are temporally switched. By setting the number of divisions of the first frequency dividing means 32 to 3, the output of the first frequency dividing means 32 becomes 1683 to 184
The frequency becomes 3 MHz, and is switched to the down converter 4 and the up converter 26 and input. Therefore 1895.
15 to 197.95 MHz received RF signal 200M
Hz reception IF signal and 200MHz
Can be converted into the same transmission RF signal as the reception RF signal. At this time, the second RF local oscillator 31 is not used.

In the 2.4 GHz wireless LAN, the connection of the switch is the same as that of the PHS. By setting the frequency division number of the first frequency dividing means 32 to 2, the output of the first frequency dividing means 32 becomes 25
The frequency becomes 25 to 2765 MHz, and is switched to the down converter 4 and the up converter 26 for input. Therefore, the received RF signal of 2402 to 2484 MHz is
Hz reception IF signal and 200MHz
Can be converted into the same transmission RF signal as the reception RF signal.

In the 5 GHz wireless LAN, the connection of the switch is the same as that of the PHS. By setting the frequency division number of the first frequency dividing means 32 to 1, the output of the first frequency dividing means 32 becomes 5050
Up to 5530 MHz, which is switched to the down converter 4 and the up converter 26 and input. Therefore 5
170 to 5230 MHz received RF signal at 200 MHz
And a 200 MHz transmission IF signal can be converted to the same transmission RF signal as the reception RF signal.

Table 1 summarizes these frequency relationships.

[Table 1]

If a × n multiplier is provided between the third switch 36 and the down converter 4 and between the fourth switch and the up converter 26, the RF local oscillator 3
The output frequencies of 0 and 31 are 1 / n. Similarly, if a harmonic mixer operating at a local oscillation signal frequency of 1 / n of the RF signal frequency is used for the down converter 4 and the up converter 26, the output frequencies of the RF local oscillators 30 and 31 will be 1 / n.

As described above, according to the present embodiment, the required number of local oscillators can be only two RFs and one IF. However, the number of local oscillators is not limited to this, and the number of local oscillators is increased, for example, by dividing the local oscillator into two, a high-frequency region and a low-frequency region, to reduce the variable frequency range per unit and to reduce noise. Can also be planned. This number may be flexibly configured according to the demand for miniaturization and weight reduction of the whole apparatus and the demand for noise reduction.

(Second Embodiment) FIG. 3 is a diagram showing a configuration of a multi-band transmitting / receiving apparatus according to a second embodiment of the present invention. The same parts as those in FIG. 1 are given the same numbers. The difference from FIG. 1 is that the switches connected to the frequency dividing means 32 and 33 are integrally formed as a matrix switch 38 having two inputs and two outputs. With such a configuration, the number of components can be further reduced, and reduction in size and weight and cost can be achieved.

(Third Embodiment) FIG. 4 is a diagram showing a configuration of a multi-band transmitting / receiving apparatus according to a third embodiment of the present invention. The difference from FIG. 1 is that the output of the first frequency dividing means 32 is divided into two and the first switch 34 and the third switch 3
6, the output of the second frequency dividing means 33 is divided into two and inputted to the second switch 35 and the fourth switch 37,
One end of the output of the first switch 34 and one end of the output of the second switch 35 are connected and input to the downconverter 4, and one end of the third switch 36 and the fourth switch 3
7 is connected to the up-converter 26 and the other end of the switch is connected to the terminating resistors 40, 41, 4
2, 43 are provided between the ground and the ground. Opening one end of the distribution signal affects the other end, so a terminating resistor is provided to prevent this effect. When inputting the output of the first frequency dividing means 32 to the down converter 4, the input of the first switch 34 is connected to the input of the down converter 4, and the input of the second switch 35 is connected to the terminating resistor 41. At this time, in the case of the FDD system, since the output of the second frequency dividing means 33 is input to the up-converter 26, the input of the fourth switch 37 is connected to the input of the up-converter 26 and the third switch 36 is connected. Is connected to the terminating resistor 42. On the other hand, in the case of the TDD system, the same output of the first frequency dividing means 32 as that of the down converter 4 is input to the up converter 26, so that the input of the third switch 36 is connected to the input of the up converter 26 and Of the switch 37 is connected to the terminating resistor 43. Therefore, at this time, there is no need to temporally switch the switch between transmission and reception even in the TDD system.

(Fourth Embodiment) FIG. 5 is a diagram showing a configuration of a multi-band transmitting / receiving apparatus according to a fourth embodiment of the present invention. The difference from FIG. 1 is that the output of the low-noise amplifier 3 is input to a quadrature demodulator 50 composed of mixers 9 and 10 and a π / 2 phase shifter 8 without being once down-converted to IF in a receiving circuit. It has a so-called direct conversion configuration in which the signal is converted into two reception baseband signals having a phase difference of π / 2. π / 2
This is a so-called direct modulation configuration in which the signal is input to a quadrature modulator 51 constituted by the phase shifter 20 and the adder 23, and the output is not a transmission IF signal but a direct transmission RF signal.

In the transmitting / receiving apparatus of this embodiment, the IF frequency of the transmitting and receiving circuits is set to 0, the local oscillator of the IF is omitted, and the local oscillator of the RF is changed to the first RF local oscillator 30 and the second RF local oscillator. The configuration is such that two oscillators 31 are provided.

In the FDD system, two RF local oscillators are used together to fix the switch. In the TDD system, one of the two RF local oscillators is used.
The switch is configured to switch between transmission and reception.

The operation of this embodiment will be described by taking the following wireless system as an example. 1. PDC800M: FDD system, reception frequency 810
-885 MHz, transmission frequency 898-956 MHz 2. PHS: TDD system, transmission / reception frequency 1895.15
-197.995 MHz 3.2.4 GHz wireless LAN: TDD system, transmission / reception frequency 2402 to 2484 MHz 4.5 GHz wireless LAN: TDD system, transmission / reception frequency 5170 to 5230 MHz

The variable frequency range of the first RF local oscillator 30 is 4804-5310 MHz (fractional bandwidth 10%),
The variable frequency range of the RF local oscillator 31 is 5388-6.
004 MHz (11% relative bandwidth).

In the PDC800M, the first switch 34
And the third switch 36, and the second switch 35 and the fourth switch 37. Also the first R
First frequency dividing means 32 connected to F local oscillator 30
Is set to 6, the output of the first frequency dividing means 32 becomes 801 to 885 MHz, and the mixer 9 and the π / 2
The signal is input to the mixer 10 via the phase shifter 8. Therefore, a signal having a reception frequency of 810 to 885 MHz can be converted into a reception baseband signal. On the other hand, by setting the frequency division number of the second frequency divider connected to the second RF local oscillator 31 to 6, the output of the second frequency divider becomes 898 to 1001 MHz, and the mixer 21 and the π The signal is input to the mixer 22 via the / 2 phase shifter 20. Therefore, the transmission baseband signal can be converted to a transmission frequency of 898 to 956 MHz.

In the PHS, the connection between the second switch 35 and the third switch 36 and the connection between the second switch 35 and the fourth switch 37 are switched according to transmission and reception times.
By setting the frequency division number of the second frequency dividing means 33 to 3, the output of the second frequency dividing means 33 becomes 1796 to 2001 MHz. Therefore, the received RF signal of 1895.15 to 1917.95 MHz can be converted into a received baseband signal, and
The transmission baseband signal can be converted into the same transmission RF signal as the reception RF signal. At this time, the first RF local oscillator 30 is not used.

In the 2.4 GHz wireless LAN, the first switch 34, the third switch 36, and the first switch 34
And the connection with the fourth switch 37 are switched according to the transmission and reception time. By setting the number of divisions of the first frequency dividing means 32 to 2, the output of the first frequency dividing means 32 becomes 2402-2655.
MHz. Therefore, the received RF signal of 2402 to 2484 MHz can be converted into a received baseband signal,
The transmission baseband signal can be converted into the same transmission RF signal as the reception RF signal. At this time, the second RF local oscillator 31 is not used.

In the 5 GHz wireless LAN, the connection of the switch is the same as that in the 2.4 GHz wireless LAN. By setting the number of divisions of the first dividing means 32 to 1, the first dividing means 32
Is 4804 to 5310 MHz. Therefore 51
The receiving RF signal of 70 to 5230 MHz can be converted into a receiving baseband signal, and the transmitting baseband signal can be converted into the same transmitting RF signal as the receiving RF signal.

Table 2 summarizes these frequency relationships.

[Table 2]

If a multiplier or a harmonic mixer is used, the output frequencies of the local oscillators 30 and 31 can be reduced. Further, the four switches can be integrally configured as a matrix switch having two inputs and two outputs to further reduce the number of parts.

As described above, according to this embodiment, the number of required local oscillators can be reduced to only RF2.

[0044]

As described above, according to the present invention,
The number of local oscillators required for the multiband transmitting / receiving device can be reduced, and the device can be reduced in size, weight, power consumption, and cost.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a multiband transmitting / receiving apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation in a TDD scheme of the multiband transmitting / receiving apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a multiband transmitting / receiving apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of a multiband transmitting / receiving apparatus according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a multiband transmitting / receiving apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a conventional FDD transmission / reception apparatus.

FIG. 7 is a diagram illustrating a configuration of a conventional transmission / reception apparatus for the TDD scheme.

[Explanation of symbols]

 Reference Signs List 1 antenna 2 antenna duplexer 3 low-noise amplifier 4 down-converter 6 band-pass filter 7 local oscillator of IF 8 π / 2 phase shifter 9, 10 mixer 11, 12 low-pass filter 13, 14 AD converter 15 baseband processing circuit 16 , 17 DA converter 18, 19 Low-pass filter 20 π / 2 phase shifter 21, 22, Mixer 23 Adder 24 Band-pass filter 26 Up-converter 27 High-power amplifier 30 First RF local oscillator 31 Second RF local oscillator 32 First frequency dividing means 33 Second frequency dividing means 34 First switch 35 Second switch 36 Third switch 37 Fourth switch 38 Two-input two-output matrix switch 40, 41, 42, 43 Terminating resistor 50 Quadrature demodulator 51 Quadrature modulator

Claims (2)

[Claims] 1. A multi-band transmitting / receiving apparatus for communicating in a plurality of radio frequency bands, comprising: a first local oscillator; a second local oscillator; and a dividing ratio to which an output of the first local oscillator is input. A first frequency dividing means having a variable frequency division ratio, a second frequency dividing means having a variable frequency division ratio to which an output of the second local oscillator is inputted, and a reception intermediate frequency having a radio frequency reception signal inputted thereto. A down converter that outputs a signal; an up converter that receives a transmission intermediate frequency signal and outputs a transmission signal of a radio frequency; an output of the first frequency divider and an output of the second frequency divider that reduce the output; A switch for switching and inputting to a local oscillation signal input terminal of a converter and a local oscillation signal input terminal of the upconverter, wherein the reception intermediate frequency and the transmission intermediate frequency are the same, In the FDD system, the output of the first frequency dividing means is input to the local oscillation signal input terminal of the down converter or the local oscillation signal input terminal of the up converter via the switch, and the second frequency dividing means An output is input to the input terminal to which the output of the first frequency dividing means is not input among the local oscillation signal input terminal of the down converter and the local oscillation signal input terminal of the up converter, via the switch, And inputting either one of the output of the first frequency dividing means and the output of the second frequency dividing means to a local oscillation signal input terminal of the down converter and a local oscillation signal input terminal of the up converter. A multi-band transmitting / receiving apparatus characterized by the above-mentioned. 2. A multi-band transmitting / receiving apparatus for performing communication in a plurality of radio frequency bands, comprising: a first local oscillator; a second local oscillator; and a division ratio to which an output of the first local oscillator is input. A first frequency dividing means having a variable frequency division ratio; a second frequency dividing means having a variable frequency division ratio to which an output of the second local oscillator is inputted; and a base band receiving a radio frequency reception signal inputted thereto. A quadrature demodulator that outputs a signal, a quadrature modulator that receives a transmission baseband signal and outputs a radio frequency transmission signal, and outputs an output of the first frequency divider and an output of the second frequency divider. A switch for switching and inputting to a local oscillation signal input terminal of the quadrature demodulator and a local oscillation signal input terminal of the quadrature modulator. In the FDD system, an output of the first frequency dividing means is output to the quadrature demodulator. Local oscillation signal input A terminal or a local oscillation signal input terminal of the quadrature modulator is inputted through the switch, and an output of the second frequency dividing means is output to a local oscillation signal input terminal of the quadrature demodulator and a local oscillation signal of the quadrature modulator. An input terminal of the input terminals to which the output of the first frequency divider is not input is input via the switch. In the TDD system, the output of the first frequency divider and the second frequency divider are provided. A multi-band transmission / reception device, wherein one of the outputs is input to a local oscillation signal input terminal of the quadrature demodulator and a local oscillation signal input terminal of the quadrature modulator.