JPH11330992A - Transmitting circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily adjust a transmission output without exerting the influence on high-frequency characteristics on a device, circuit components, etc. SOLUTION: This circuit is equipped with a VCO 24 for a 1st local oscillator which outputs a 1st local oscillation signal, an oscillation output adjusting circuit 26 which adjusts the output level of the 1st local oscillation signal outputted from the VCO 24 for the 1st local oscillator, a multiplying circuit 27 which multiplies the frequency of the 1st local oscillation signal obtained by the oscillation output adjusting circuit 26, and a transmission block 22 including an up- converter 29 which converts the frequency of a modulated signal to be transmitted to a carrier frequency band with the 1st frequency-multiplied local oscillation signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transmission circuit of a communication device such as a PHS terminal.

[0002]

2. Description of the Related Art PHS (Personal Handy)
FIG. 3 shows a general configuration of a transmission circuit used in a transmission system circuit of a terminal (phone system: simplified cordless telephone system).

In FIG. 1, reference numeral 11 denotes a local oscillation block, and reference numeral 12 denotes a transmission block. The local oscillation block 11 includes a PLL circuit 13, a first local oscillator VCO 14, and a second local oscillator VCO 15.

[0004] The transmission block 12 includes a modulator (MO).
D) 16, up-converter 17, transmission power adjustment circuit 1
8 and a driver amplifier 19. The first local oscillator VCO 14 of the local oscillation block 11 constitutes a first charge pump together with the PLL circuit 13, and receives a 1.6 GHz band first local oscillation signal in the receiving block and the transmitting block (not shown). 12 to the up-converter 17.

The second local oscillator VCO 15 constitutes a second charge pump together with the PLL circuit 13. The second local oscillator VCO 15 transmits the second local oscillation signal in the 240 MHz band to a receiving block (not shown) and the modulator 16 as well. Output.

The modulator 16 responds to the IQ signal output from the modem (not shown) at the preceding stage by the second local oscillator VCO.
Using the second local oscillation signal in the 240 MHz band from 15 to 15, modulation is performed in the π / 4 shift QPSK system and transmitted to the up-converter 17.

The up-converter 17 further converts the frequency of the modulated signal using the first local oscillation signal in the 1.6 GHz band from the first local oscillator VCO 14 to obtain a carrier frequency band ( 1.6GHz + 2
40 MHz =) A transmission signal in the 1.9 GHz band is obtained and transmitted to the transmission power adjustment circuit 18.

The transmission power adjusting circuit 18 controls the transmission signal transmitted from the up-converter 17 so that the output of the transmission power amplifying circuit (not shown) at the subsequent stage of the transmission block 12, that is, the output level of the final stage becomes appropriate. Is adjusted and output to the driver amplifier 19.

The driver amplifier 19 amplifies the transmission signal adjusted by the transmission power adjustment circuit 18 with a constant amplification factor, outputs the amplified signal to the transmission power amplifier circuit at the next stage, and outputs the same from an antenna (not shown).

[0010]

As described above, the transmission power adjusting circuit 18 is arranged at the subsequent stage of the up-converter 17, and is adapted for transmitting a frequency-converted transmission signal to a 1.9 GHz band which is a carrier frequency band. The power is adjusted. Therefore, there are many design problems, such as the devices and components to be used are easily affected by the VSWR (voltage standing wave ratio) at the antenna and the specified adjustment range may not be satisfied.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to easily adjust a transmission output without affecting high-frequency characteristics of devices and circuit components. It is an object of the present invention to provide a transmission circuit capable of

[0012]

According to the first aspect of the present invention,
First local oscillation means for outputting a first local oscillation signal;
First adjusting means for adjusting the output level of the first local oscillation signal output from the first local oscillation means, and frequency-multiplying the first local oscillation signal obtained by the first adjusting means. It is characterized by comprising multiplying means and frequency converting means for frequency-converting a modulated signal to be transmitted to a carrier frequency band by the first local oscillation signal frequency-multiplied by the multiplying means.

With this configuration, the output level of the first local oscillation signal having a sufficiently low frequency is adjusted, then the frequency is multiplied, and the modulated signal is frequency-converted to the carrier frequency band by using this. Therefore, it is possible to easily adjust the transmission output without affecting the devices and circuit elements due to the high-frequency characteristics in performing the output adjustment.

According to a second aspect of the present invention, in the first aspect of the present invention, the second local oscillation means for outputting a second local oscillation signal and the second local oscillation means output from the second local oscillation means are provided. And a second adjusting means for adjusting the output level of the local oscillation signal. The modulation signal is obtained by performing modulation using the second local oscillation signal obtained by the second adjusting means. And supplying the obtained modulated signal to the frequency conversion means.

With such a configuration, in addition to the operation of the first aspect of the present invention, the output level of the second local oscillation signal used for obtaining the modulation signal from the transmission data is sufficiently low with respect to the frequency. Is adjusted, the transmission output can be adjusted more accurately without causing the device and circuit components and the like to be affected by the high-frequency characteristics.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a transmission circuit used in a transmission system of a PHS terminal will be described below with reference to the drawings. FIG. 1 shows the circuit configuration, in which reference numeral 21 denotes a local oscillation block, reference numeral 22 denotes a transmission block, and the local oscillation block 21 is a PLL circuit 2.
3. VCO 24 for first local oscillator, VCO for second local oscillator
It comprises a CO 25, an oscillation output adjustment circuit 26, and a multiplication circuit 27.

The transmission block 22 includes a modulator 28,
It comprises an up-converter 29 and a driver amplifier 30. The first local oscillator VCO 24 of the local oscillation block 21 forms a first charge pump with the PLL circuit 23, and outputs, for example, a first local oscillation signal in a 140 MHz band to the oscillation output adjustment circuit 26.

The oscillation output adjustment circuit 26 adjusts the gain or attenuation so that the level of the first local oscillation signal from the first local oscillator VCO 24 becomes appropriate, and outputs the adjusted signal to the multiplication circuit 27.

The multiplying circuit 27 multiplies the transmitted first local oscillation signal by a predetermined multiplication factor, for example, 11 multiplication. The output in the 1.6 GHz band is received by the reception block (not shown) and the transmission block 22. To the up-converter 29.

The second local oscillator VCO 25 constitutes a second charge pump together with the PLL circuit 23. The second local oscillator VCO 25 sends a 240 MHz band second local oscillation signal to a receiving block (not shown) and the modulator 28. Output.

The modulator 28 responds to the IQ signal output from the modem (not shown) at the preceding stage by the second local oscillator VCO.
Using the second local oscillation signal in the 240 MHz band from 25, the signal is subjected to π / 4 shift QPSK modulation and transmitted to the up-converter 29.

In the up-converter 29, the modulated 240 MHz band π / 4 shift QPSK signal is further frequency-multiplied by the multiplication circuit 27 to 1.6 GHz.
By performing frequency conversion using a signal in the z band, the carrier frequency band is (1.6 GHz + 240 MHz =) 1.9 GH.
A transmission signal in the z band is obtained and output to the driver amplifier 30.

The driver amplifier 30 amplifies the transmission signal, which has been frequency-converted by the up-converter 29, with a constant amplification factor, outputs the amplified signal to a transmission power amplifier circuit (not shown) at the next stage, and outputs the same from an antenna (not shown).

In the above configuration, a sufficiently low frequency band output from the first local oscillator VCO 24, for example, 1
The output level of the first local oscillation signal in the 40 MHz band is adjusted by the oscillation output adjustment circuit 26, and thereafter, the frequency is multiplied by a multiplication circuit 27 to a required frequency band, for example, a 1.6 GHz band, and then the upconverter 29. It was to be offered to.

Therefore, devices and circuit components which actually constitute the oscillation output adjustment circuit 26 are not affected by restrictions or adverse effects on high-frequency characteristics, and design problems can be solved.

In the above embodiment, the signal level is adjusted only for the first local oscillation signal output from the first local oscillator VCO 24. However, the second local oscillator VCO 25 The signal level of the second local oscillation signal used for the output modulation may also be accurately adjusted.

FIG. 2 shows another configuration example of such an embodiment of the present invention, which is basically the same as that shown in FIG. 1 above. And the description is omitted.

However, in the local oscillation block 21 ',
Further, an oscillation output adjustment circuit 31 is provided. The oscillation output adjustment circuit 31 increases or decreases the gain or attenuation to adjust the signal level of the 240 MHz band second local oscillation signal output from the second local oscillator VCO 25 to be constant. The later second local oscillation signal is supplied to the modulator 28 of the transmission block 22.

In the above configuration, the modulator 28
The 240 MHz band second from the second local oscillator VCO 25 used for performing π / 4 shift QPSK modulation on an IQ signal output from a modem (not shown) at the preceding stage.
The level of the local oscillation signal is also adjusted by the oscillation output adjustment circuit 3.
1 allows for constant adjustment.

Therefore, devices and circuit components which actually constitute the oscillation output adjustment circuit 31 for performing adjustment in a relatively low frequency band of 240 MHz are not affected by restrictions or adverse effects on high-frequency characteristics, and there is a problem in design. , It is possible to perform accurate modulation operation and transmission power adjustment.

Although the above embodiment has been described with reference to a case where the present invention is applied to a transmission output adjustment circuit used in a transmission system of a PHS terminal, the present invention is not limited to this. Of course, other communication terminals can be applied. In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0032]

According to the first aspect of the present invention, the output level of the first local oscillation signal having a sufficiently low frequency is adjusted, and then the frequency is multiplied. Since the frequency conversion is performed, the transmission output can be easily adjusted without affecting the devices and circuit elements due to the high-frequency characteristics in performing the output adjustment.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, the second local oscillation signal used for obtaining the modulation signal from the transmission data has a sufficiently low frequency. Since the output level is adjusted, it is possible to more accurately adjust the transmission output without affecting the high-frequency characteristics of devices and circuit components when adjusting the output.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration according to an embodiment of the present invention.

FIG. 2 is a block diagram showing another circuit configuration of the embodiment.

FIG. 3 is a block diagram showing a configuration of a general transmission output adjustment circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Local oscillation block 12 ... Transmission block 13 ... PLL circuit 14 ... 1st local oscillator VCO 15 ... 2nd local oscillator VCO 16 ... Modulator 17 ... Upconverter 18 ... Transmission power adjustment circuit 19 ... Driver amplifier 21, 21 '... Local oscillation block 22 ... Transmission block 23 ... PLL circuit 24 ... VCO for first local oscillator 25 ... VCO for second local oscillator 26 ... Oscillation output adjustment circuit 27 ... Multiplier circuit 28 ... Modulator 29 ... Up converter 30 ... Driver Amplifier 31: oscillation output adjustment circuit

Claims (2)

[Claims] 1. A first local oscillation means for outputting a first local oscillation signal, and a first adjustment means for adjusting an output level of the first local oscillation signal output from the first local oscillation means. Multiplying means for multiplying the frequency of the first local oscillation signal obtained by the first adjusting means; and modulating the modulated signal to be transmitted by the first local oscillation signal frequency-multiplied by the multiplying means by the carrier frequency. A transmission circuit comprising: frequency conversion means for performing frequency conversion up to a band. 2. A second local oscillation means for outputting a second local oscillation signal, and a second adjusting means for adjusting an output level of the second local oscillation signal output from the second local oscillation means. Further comprising: obtaining a modulation signal obtained by performing modulation using the second local oscillation signal obtained by the second adjustment means, and supplying the obtained modulation signal to the frequency conversion means. The transmission circuit according to claim 1, wherein: