JP3320427B2 - Power control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power control device such as a high-frequency power amplifier of a radio device.

[0003]

2. Description of the Related Art Recently, mobile communications such as automobile telephones have been very frequently used. In mobile communications, the need for confidential communication and the diversification of transmission information have led to a shift from modulation of audio signals by analog signals to modulation by digital signals.

In digital communication, TDMA (TIM
Data transmission / reception is performed with respect to each other's communication device for each time slot time-divided by E DIVISION MULTIPLEX ACCESS).

On the other hand, for example, in a portable telephone device,
Since long-term use with a limited battery is required, low power consumption is an essential condition. In order to reduce the power consumption, it is important to minimize the power of the power amplification of the transmitting unit that consumes much power in the portable telephone device. For this purpose, APC (AUTOMATIC POWER CON
TROL) circuit is provided.

FIG. 4 is a diagram showing a configuration of a conventional APC circuit.

As shown in FIG. 1, a digital signal is modulated by a modulator 1 and a high-frequency signal is attenuated by a variable attenuator 2 by a predetermined level. Thereafter, the power is amplified by the power amplifier 3, and the transmission power is supplied to the antenna through the directional coupler 4 and the isolator 5. Then, a part of the radio wave radiated from the directional coupler 4 is detected as a direct current by the detection diode 6 and the resistor 7. Further, the high-frequency component superimposed on the DC current is cut by the low-pass filter 8. On the other hand, a signal S1 based on a predetermined transmission output level is sent to the operational amplifier 9 from a control device (not shown). And low pass filter 8
Is compared with the signal S1, and the variable attenuator 2 is controlled with a voltage based on the difference between the voltages of these signals to control the amount of power attenuation so that the power is kept constant.

However, in digital linear modulation,
Modulation data causes carrier amplitude fluctuation,
The APC circuit has a problem in that the transmission output fluctuates in response to the modulated data, and a ramp-shaped transmission output cannot be obtained.

[0009]

As described above, in the conventional power control circuit, when controlling a modulated high-frequency signal by digital linear modulation or the like, the control follows amplitude fluctuations of modulated data. There is a problem that the transmission output fluctuates and a ramp-shaped transmission output cannot be obtained. The present invention has been conceived to solve such a problem.When controlling the output power of a high-frequency signal modulated by digital linear modulation or the like, the present invention is not affected by the amplitude fluctuation of the modulation data, and has a ramp shape. An object of the present invention is to provide a power control device capable of starting a transmission output.

[Structure of the Invention]

[0011]

To achieve the above object, according to the Invention The first aspect of the present invention, a damping means for attenuating the input signal, prior to
Amplifying means for amplifying the serial attenuated signal, and the signal strength detecting means for detecting the signal strength of the amplified signal, a signal corresponding to the signal strength shall be the target at the output of said amplifying means is previously held Comparing the detected signal strength with a reference value.
Comparing means for outputting a voltage corresponding to the comparison result of
After starting burst transmission of the voltage output by the comparison means
Sampling at the timing of
Until the timing after the next burst transmission rises
Having a sample and hold circuit for holding
The output of the sample and hold circuit and the target output
A power control apparatus and controls the attenuation factor of the attenuation section based on both the held signal to応信No. retaining means, the second invention, an amplifying means for amplifying an input signal, the Signal strength detecting means for detecting the signal strength of the amplified signal ; and a target on the output side of the amplifying means.
And the target output corresponding signal holding means signals corresponding to the signal strength is held in advance that, the detected signal strength
Is compared with a reference value, and a voltage corresponding to the comparison result is output.
Comparing means for outputting the voltage output by the comparing means;
Sampling at the timing after the start of
Start of next burst transmission of sampled voltage
Sample and hole to hold until later timing
And a output circuit of the sample and hold circuit.
Characterized by controlling the amplification factor of the amplification means based on both the force and signal held in the target corresponding signal holding means <br/>
A third aspect of the present invention is the power control apparatus according to the first or second aspect, wherein the amplifying means is a high-frequency power amplifier of a transmitter used for communication by time division multiplexing, wherein An electric power control apparatus characterized in that an initial setting of a transmission output is sometimes performed based on a signal stored in the target output holding means.

[0012]

According to the power control apparatus of the present invention, the output signal level amplified by the amplifying means and the signal corresponding to the target output signal strength from the amplifying means held by the target output corresponding signal holding means are used. The level of the output signal is controlled.

Therefore, the output signal level of the amplifying means becomes constant. For example, when the transmitter of the TDMA system is used for burst transmission at the start of a transmission slot, fluctuation of transmission output due to amplitude fluctuation due to modulation is reduced. Can be.

[0014]

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

FIG. 1 is a diagram showing the configuration of an embodiment of the power control device of the present invention when applied to a wireless telephone device.

The power control device 10 shown in FIG.
Variable attenuator 12 that attenuates a high-frequency signal digitally modulated by a digital amplifier, and a power amplifier 13 that amplifies power of the high-frequency signal output from the variable attenuator 12
A directional coupler 14 for passing a high-frequency signal power-amplified by the power amplifier 13 in one direction; a detection diode 15 for detecting the electric field intensity of a radio wave radiated from the directional coupler 14; A low-pass filter 16 that cuts off a high-frequency signal superimposed on the DC detected by the DC-DC converter, a DC voltage output from the low-pass filter 15 and a reference voltage sent from the control circuit 17 are compared, and the difference between these voltages is determined. And a sample-and-hold circuit 1 that samples and holds a signal output from the operational amplifier 18 at a timing sent from the control circuit 17.
9, a preset voltage generating circuit 20 for generating a preset voltage corresponding to the transmission level, and an adder 21 for adding the preset voltage from the preset voltage generating circuit and the output voltage from the sample and hold circuit 19. . The attenuation rate of the variable attenuator 12 changes according to the output voltage of the adder 21.

Next, the operation of the power control device having the above configuration will be described.

FIG. 2 is a diagram showing TDMA time slots and sample timing and hold time of the sample and hold circuit 19.

As shown in FIG. 1A, the first frame F
L1 is divided into a transmission slot SL1, a reception slot SL2, and an empty slot SL3.

In response to an instruction from the control circuit 17, the preset voltage generation circuit 20 generates a preset voltage that is at the transmission output level. Further, a voltage corresponding to the transmission level is supplied from the control circuit 17 to a reference voltage input of the operational amplifier 18. Further, a radio wave radiated very slightly from the directional coupler 14 is detected by the detection diode 15, and a high-frequency component is cut off and input to the operational amplifier 18. Operational amplifier 18
Then, a voltage corresponding to the difference between the reference voltage input sent from the control circuit 17 and the DC signal detected by the detection diode 15 is output. Then, this voltage is input to the sample and hold circuit 19. The directional coupler 1
Most of the power input to 4 is supplied to an antenna (not shown) via the isolator 22 and radiated as radio waves. First, the first transmission slot SL1 shown in FIG.
Then, the transmission output is controlled by roughly adjusting the control voltage of the variable attenuator 12 with the preset voltage. The sample-and-hold circuit 19 is set in the hold mode to make the control voltage of the variable attenuator 12 constant. The output signal from the modulator 11 rises in a ramp shape so that the transmission output has a ramp waveform. Thereafter, the sample and hold circuit 19
Is switched to the sample mode once at time T1 in FIG.
In the remaining transmission time slot SL1, the output signal of the sample and hold circuit 19 for fine adjustment and the preset voltage for coarse adjustment are added by the addition circuit 21 and output to the variable attenuator 12, so that the transmission output level is constant. Control so that

The ramp waveform at the time of the fall at the end of the transmission slot is realized by ramping up the modulation signal from the modulator 11 in the same manner as at the time of the rise.

After the second transmission slot SL4, the output of the sample and hold circuit 19 used in the first transmission slot is set to the hold mode, and the output of the sample and hold circuit 19 and the transmission level from the preset voltage generation circuit are set in accordance with the output. The attenuation amount of the variable attenuator 12 is controlled based on the voltage obtained by adding both of the preset voltage and the signal from the modulator 11 in a ramp shape. After the rise of this signal is completed, the sample-and-hold circuit 19 is sampled in the sample mode at time T2 at a high speed, sampled, and held again, and in the remaining transmission slot SL4, the output of the sample-and-hold circuit 19 is output. The variable attenuator 12 is controlled by the signal and the coarse adjustment preset signal, and the transmission output is made constant. Also, at the time of falling, the output signal from the modulator 11 falls like a ramp in the same manner as at the time of rising, so that the transmission output has a ramp waveform.

FIG. 3 is a diagram showing the configuration of another embodiment of the power control device of the present invention.

In this embodiment, two variable attenuators 12a and 12b are provided, and a preset voltage generation circuit 20 is provided.
The variable attenuator 12a is directly controlled by the preset voltage output from the controller and coarsely adjusted, while the output of the sample and hold circuit 19 directly controls the variable attenuator 12b.
May be controlled for fine adjustment.

In the above-described embodiment, the transmission output is controlled by inserting a variable attenuator on the input side of the power amplifier 13. However, the amplification gain of the power amplifier 13 may be controlled.

Therefore, in the power control device of this embodiment,
Even at the time of burst transmission in a transmission slot, coarse adjustment is performed in advance by a preset voltage corresponding to the transmission level, and fine adjustment is performed by a control signal fed back in a short time after the start of burst transmission. High-speed control can be performed, and furthermore, it is possible to suppress the spread of the spectrum when each burst rises and falls.

[0027]

According to the power control apparatus of the present invention, the output signal level amplified by the amplifying means and the signal corresponding to the target output signal strength from the amplifying means held in the target output corresponding signal holding means. And the level of the output signal is controlled based on the above, so that the output signal level of the amplifying means becomes constant.

For example, when used in burst transmission at the start of a transmission slot of a TDMA-type transmitter, fluctuations in transmission output due to fluctuations in amplitude due to modulation can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a power control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing TDMA time slots and sample timing and hold time of a sample and hold circuit.

FIG. 3 is a diagram showing a configuration of another embodiment of the power control device of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional power control device.

[Explanation of symbols]

 12, 12a, 12b Variable attenuator 13 Power amplifier 14 Directional coupler 15 Detection diode 16 Low-pass filter 17 Control circuit 18 Operational amplifier 19 Sample-and-hold circuit 20 Preset voltage generation circuit 21 Adder

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tatsuya Yamada 3-1-1 Asahigaoka, Hino-shi, Tokyo In-house Toshiba Hino Plant (56) References JP-A-60-33719 (JP, A) 1-309418 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H03G 3/20-3/34

Claims (3)

(57) [Claims] And 1. A damping means for attenuating an input signal, and amplifying means for amplifying the attenuated signal, and the signal strength detecting means for detecting the signal strength of the amplified signal, at the output of said amplifying means and the target output corresponding signal holding means signals corresponding to the signal strength shall be the target is held in advance, it is compared with a reference value to the detected signal strength results comparison
Comparing means for outputting a voltage corresponding to the above,
Sampling is performed at the timing after the
Timing after the start of the next burst transmission
With a sample and hold circuit
And, wherein the target output and the output of the sample-and-hold circuit
A power control device, wherein an attenuation rate of the attenuation means is controlled based on both signals held in the corresponding signal holding means . 2. A amplifying means for amplifying an input signal, and the signal strength detecting means for detecting the signal strength of the amplified signal, a signal corresponding to the signal strength shall be the target at the output of said amplifying means The target output corresponding signal holding means held in advance, and comparing the detected signal strength with a reference value,
Comparing means for outputting a voltage corresponding to the above,
Sampling is performed at the timing after the
Timing after the start of the next burst transmission
With a sample and hold circuit
And, wherein the target corresponds to an output of the sample-and-hold circuit
The increase is performed based on both the signals held in the signal holding means.
Power control apparatus and controls the amplification ratio of width means. 3. The amplifying means is a high-frequency power amplifier of a transmitter used for time-division multiplexing communication, and performs transmission output based on a signal stored in the target output holding means at the time of burst transmission in a transmission slot. 3. The power control device according to claim 1, wherein an initial setting is performed.