JP3289197B2 - Transmission power amplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power amplifier for a shared mobile telephone system of an analog system and a digital system, and relates to a configuration of a transmission power amplifier which can be most efficiently used for both systems by using a single nonlinear power amplifier. It is about.

[0002]

2. Description of the Related Art A conventional analog car telephone system is a modulation system of a constant amplitude by FM modulation, and a high efficiency non-linear power amplifier such as a class F operation is usually used as a transmission power amplifier. On the other hand, the digital car telephone system employs a modulation method in which amplitude fluctuations are caused by π / 4 shift QPSK modulation, so that a linear amplifier is used or the transmission power amplification disclosed in Japanese Patent Application Laid-Open No. 3-174810. Use the device. This device is provided with a DC voltage conversion circuit 11 for controlling the drain voltage of the nonlinear power amplifier 3 as shown in FIG. 4, detects the input signal level by the envelope detection circuit 5, and uses the output as an input signal,
A correction circuit for detecting an output signal level by an envelope detection circuit, obtaining a difference signal between the output signal level and the input signal level by a difference signal generation circuit, and inputting the difference signal as a correction signal;
Since the DC voltage conversion circuit 11 is controlled by the output signal, it is characterized by high efficiency.

Therefore, in an automobile telephone sharing system that shares an analog system and a digital system, a nonlinear power amplifier 23 and a linear power amplifier 24 are connected in parallel as shown in FIG. At the time, the power was switched to the nonlinear power amplifier 23, and at the time of the digital system, the power was switched to the linear power amplifier 24.

There is also a method of using only a linear power amplifier 31 having a lower efficiency than a nonlinear amplifier and using it in a shared system of an analog system and a digital system as shown in FIG. 3 in a linear amplification region.

[0005]

However, in the case of the conventional switching system shown in FIG. 2, not only two types of power amplifiers are required, but also the efficiency is reduced due to the loss of the switches 21 and 22. is there. When one linear amplifier 31 of FIG. 3 is used in common, the efficiency of the linear amplifier is lower than that of the high-efficiency nonlinear amplifier used in the analog system, so that the efficiency is deteriorated in the analog system. There is the problem of being inappropriate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an efficient transmission power amplifying apparatus which eliminates the above-mentioned problems and which can be shared between an analog system and a digital system using a single nonlinear power amplifier circuit. The purpose is to do.

[0007]

According to the present invention, there is provided a DC voltage conversion circuit 11 for controlling a voltage supplied to a power supply terminal of a nonlinear amplifier 3 as shown in FIG. 3 are provided on the input side and the output side of the circuit 3 for detecting the signal level. The difference between the two signals is obtained by a difference signal generating circuit 8, and the output signal is used as a correction signal, and the envelope on the input side is used. The output signal is input to the correction circuit 10 together with the output signal of the detection circuit 5, and the output signal is input to the DC voltage conversion circuit 11 to control the drain (or collector) voltage of the element used in the nonlinear amplifier 3. Further APC
(Automatic power control) circuit 7 and switch 12 are provided, and the voltage of nonlinear amplifier 3 is controlled from envelope detection circuit 6 on the output side of nonlinear amplifier 3 via APC (automatic power control) circuit 7 and switch 12 The greatest feature of the present invention is that means for performing power amplification of both digital and analog systems is provided.

[0008]

According to the present invention, the transmission power is controlled by setting the drain (or collector) voltage so that the nonlinear amplifier 3 operates in class F by the APC circuit 7 in the analog mode in the analog mode, and the switching is performed in the digital mode. Vessel 1
2 operates as a switching linear power amplifier and controls transmission power by the attenuator 1. For this reason, it is possible to use the most efficient power amplification method for both types.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the transmission power amplifying device of the present invention. As shown in the figure, the apparatus includes an attenuator 1, a directional coupler 2, a non-linear amplifier (high-frequency power amplifier) 3, a directional coupler 4, an envelope detection circuit 5, an envelope detection circuit 6, an APC circuit 7, a difference signal Generation circuit 8, DC amplifier 9, correction circuit 10, DC voltage conversion circuit 11, switch 1
2. It is composed of an antenna 13.

The operation of the analog system will be described below. At the time of the analog system operation, the switch 12 is tilted to the side a to set the attenuation of the attenuator 1 to the minimum. The high-frequency modulated input signal is input to the nonlinear amplifier 3 via the attenuator 1 and the directional coupler 2, and the output signal is supplied to the antenna 13 via the directional coupler 4.
Sent from The secondary output signal of the directional coupler 4 is detected as an output level by an envelope detection circuit 6 and is detected by an APC circuit 7.
Is compared with the analog control signal, and the output signal controls the drain (or collector) voltage of the element used in the nonlinear amplifier 3 via the switch 12.

The analog control signal is a signal for controlling the transmission power level in the analog mode, and is a voltage determined according to several types of transmission power levels. The transmission power is set by the designation from the base station at the beginning of communication. You.

Next, the operation of the digital system will be described. At the time of the digital operation, the switch 12 is turned to the b side to control the drain (or collector) voltage of the element used in the nonlinear amplifier 3 by the output signal of the DC voltage conversion circuit 11. The high frequency modulation input signal is input to the nonlinear amplifier 3 via the attenuator 1 and the directional coupler 2, and the output signal is transmitted to the antenna 13 via the directional coupler 4.

An output signal envelope of the nonlinear amplifier 3 is obtained by an envelope detection circuit 6, an input signal envelope is similarly obtained by an envelope detection circuit 5, a difference between both signals is obtained by a difference signal generation circuit 8, and an output thereof is obtained. The signal is input to the correction circuit 10 together with the output signal of the envelope detection circuit 5 on the input side as a correction signal, and the output signal is input to the DC voltage conversion circuit 11 and the drain of the element used in the nonlinear amplifier 3 (or Collector) control the voltage.

The transmission power is controlled by a digital control signal in an attenuator 1 connected in front of the nonlinear amplifier 3. The digital control signal is a signal for controlling a transmission power level in a digital system, and is a voltage determined according to several types of transmission power levels. Transmission power is set at the beginning of communication by designation from a base station.

[0015]

As described above, according to the present invention, the following excellent effects can be expected. In the analog and digital shared mobile telephone systems, a single high-frequency power amplifier can be used by switching to both the analog and digital modes. In the case of the analog system, the amplifier operates as a class F as a non-linear amplifier, and there is no need to switch large power transmitted by an output antenna, so that the efficiency is improved. A non-linear power amplifier is used when operating in an analog system, and a linear power amplifier is used when operating in a digital system. Therefore, it is possible to use the most efficient power amplification system for both systems.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a transmission power amplification device according to the present invention.

FIG. 2 is a block diagram showing a configuration example 1 of a conventional transmission power amplifier.

FIG. 3 is a block diagram showing a configuration example 2 of a conventional transmission power amplifying device.

FIG. 4 is a block diagram illustrating a configuration example of a conventional digital transmission power amplifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Attenuator 2 Directional coupler 3 Nonlinear amplifier 4 Directional coupler 5 Envelope detection circuit 6 Envelope detection circuit 7 APC circuit 8 Difference signal generation circuit 9 DC amplifier 10 Correction circuit 11 DC voltage conversion circuit 12 Switching device 13 Antenna

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-274906 (JP, A) JP-A-3-276912 (JP, A) JP-A-55-39469 (JP, A) JP-A-3-27691 174810 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H03G 3/20-3/34

Claims (1)

(57) [Claims] A high-frequency power amplifier; input detection means for obtaining an envelope of a modulated wave input to the high-frequency power amplifier; and a voltage supplied to a power supply terminal of the high-frequency power amplifier by an output signal of the input detection means. DC voltage conversion means for controlling the DC voltage conversion means, the output detection means for obtaining the envelope of the modulated wave output from the power amplifier, the difference between the output of the output detection means and the output of the input detection means to the DC voltage conversion means In a transmission power amplifier including a correction unit for correcting an input output signal of the input detection unit, a voltage supplied to the high-frequency power amplifier via a switch to a power supply terminal of the high-frequency power amplifier is controlled, and provided an automatic power control means for controlling the output of the high-frequency power amplifier, when operating in the analog mode mobile telephone system the output
The output of the detection means is input to the automatic power control means,
By the output of the dynamic power control means, the high
When controlling the voltage supplied to the power terminal of the frequency power amplifier,
In both cases, when operating with a digital car phone system,
The difference between the output of the output detection means and the output of the input detection means
The input detection input to the DC voltage conversion means by
The output signal of the means is corrected through the correction means,
The high-frequency power is supplied to the high-frequency
A transmission power amplifying device for controlling a voltage supplied to a power supply terminal of a power amplifier.