JPH07336243A - Transmission output controller - Google Patents

Abstract

PURPOSE:To reduce the current consumption by conducting power control during continuous transmission specific to the CDMA system over a wide dynamic range. CONSTITUTION:Fluctuation in the amplitude component of digital orthogonal modulation is eliminated by low pass filters 20, 22 and high speed rising/falling control of a burst wave is conducted not through the low pass filter with changeover of a switch 23, then the power control during continuous transmission is conducted over a wide dynamic range. Since a power amplifier 17 is operated with a constant gain even in the presence of fluctuation in the power supply voltage, fluctuation in frequency and the revision of an operation bias condition or the like, the current consumption is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a CDMA (Code Div).
The present invention relates to a device that controls the transmission output of a wireless communication device based on the ision Multiple Access) method.

[0002]

2. Description of the Related Art Conventionally, the transmission output control in a wireless communication device is most commonly performed by an FDMA system using analog modulation, which only needs to have a function of keeping a peak power level constant in a continuous mode. Further, in the TDMA system using digital modulation which has been put into practical use in recent years, ramp ramping (rising / falling control) of the burst and output level control over a wider dynamic range than in the past are required for the above functions. Furthermore, CDM
In the A system, in addition to the above burst ramping control, a function of switching the power level during the continuous transmission mode is required.

FIG. 4 shows the configuration of a transmission output control device in a conventional CDMA system. In this transmission output control device, the modulation wave from the transmission modulation wave generation unit 4 including the oscillator 1, the modulator 2 and the level variable amplifier 3 is amplified by the power amplifier 6 through the variable attenuator 5 and output. A part of the output is taken out by the directional coupler 7, detected by the diode detector 8, compared with the waveform of the reference ramp signal by the comparison error amplifier 9, and the variable attenuator 5 is controlled by the error output. , Is configured to control the input of the power amplifier 6.

[0004]

However, the above-mentioned C
In the DMA transmission output control device, a minimum step 0.5d is required when switching the power level during continuous transmission.
B has to be switched over a dynamic range of 80 dB or more, which is difficult to realize with the above configuration. Further, in the above configuration, it is difficult to combine the characteristic that the average output power is 10 or more dB lower than that of the analog system in the power control in the CDMA system with the reduction in power consumption.

The present invention solves such a conventional problem and is excellent in that power control during continuous transmission, which is peculiar to the CDMA system, can be performed in a wide dynamic range and that current consumption can be reduced. Another object of the present invention is to provide a transmission output control device.

[0006]

In order to achieve the above object, the present invention provides a transmission modulated wave generator, a distributor for dividing the output from the transmission modulated wave generator into two, and one output of the distributor. , A directional coupler connected to the output of the power amplifier, a first diode detector and a first low-pass filter connected in series to the output of the directional coupler, The second diode detector and the second low-pass filter connected in series to the other output of the detector, the connection point of the first diode detector and the first low-pass filter, and the output of the first low-pass filter, and the second output It is provided with a switch for switching between the output of the low-pass filter and the reference signal, and a comparison error amplifier for receiving the output of the switch and controlling the level variable element. .

[0007]

Therefore, according to the present invention, the low-pass filter eliminates the fluctuation of the amplitude component of the digital quadrature modulation, and the high-speed rise / fall control of the burst wave can be performed at high speed without passing through the low-pass filter. By switching with, the power control during continuous transmission can be performed in a wide dynamic range, and the power amplifier works as a constant gain even if the power supply voltage fluctuates, the frequency fluctuates, and the operating bias condition changes. It is possible to reduce current consumption.

[0008]

【Example】

(Embodiment 1) FIG. 1 shows the configuration of a transmission output control apparatus according to a first embodiment of the present invention. In FIG.
Reference numeral 11 is an oscillator, 12 is a modulator, and 13 is a level variable amplifier, which constitute a transmission modulated wave generator 14 driven by a constant voltage power source. Reference numeral 15 is a distributor that divides the output of the transmission modulated wave generator 14 into two, and 16 is a distributor 1.
5, a variable attenuator as a level variable element for inputting one output of 5, a power amplifier for amplifying the output of the variable attenuator 16, a directional coupler 18 connected to the output of the power amplifier 17, and a directional coupler 19. A first diode detector for obtaining a detection voltage connected to the output of the static coupler 18, 20 is a first low-pass filter connected to the first diode detector 19, and 21 is the other of the distributor 15. A second diode detector for obtaining a detection voltage connected to the output, 22 is a second low-pass filter connected to the second diode detector 21, and 23 is changeover switches 23A and 23
B is a double switch, 24 is a comparison error amplifier that receives the output of the switch 23 and controls the variable attenuator 16, 25 is a reference ramp signal, and 26 is a ramp timing signal.

The movable-side terminal a of one switch 23A of the two changeover switches 23 is the first low-pass filter 2
0, the movable side terminal b is connected to the connection point between the first diode detector 19 and the first low pass filter 20, and the fixed side terminal c is connected to the negative side terminal of the comparison error amplifier 24. . The movable side terminal d of the other switch 23B is connected to the second low pass filter 22, the movable side terminal e is connected to the reference ramp signal 25, and the fixed side terminal f.
Is connected to the positive terminal of the comparison error amplifier 24.

The transmitted modulated wave generator 14 is temperature-compensated so as not to be affected by changes in environmental conditions. Also, a variable gain amplifier can be used instead of the continuously variable attenuator 16. Further, the two low-pass filters 20 and 22 are for removing amplitude component fluctuations of digital quadrature modulation, and those having uniform characteristics of cutoff frequencies are used. Furthermore, the power amplifier 17
Is connected to the battery power source, which is the drive power source,
A current control terminal is connected to improve power conversion efficiency.

Next, the operation of the above embodiment will be described.
The modulation wave output from the transmission modulation wave generation unit 14 driven by the constant voltage power supply is divided into two by the distributor 15, one of which passes through the variable attenuator 16 and is power-amplified by the power amplifier 17 and output. A part of the output is taken out by the directional coupler 18 and divided into a signal system that passes the diode detector 19 and the low-pass filter 20 and a signal system that passes only the diode detector 19 and does not pass the low-pass filter 20. Are respectively selected by the switch 23A and input to the minus side of the comparison error amplifier 24. On the other hand, the other output distributed by the distributor 15 is the diode detector 21 and the low-pass filter 22.
This signal and the reference ramp signal pass through the switch 23B.
Is selected by the input signal and input to the plus side of the comparison error amplifier 24. The switch 23 is switched by the ramp timing signal 26, and the rising of the burst wave,
Only when falling, the movable side terminals b and e are switched to, the detection voltage with a short time constant that has passed through only the diode detector 19 is input to the minus side of the comparison error amplifier 24, and the reference lamp is added to the plus side. The signal 25 is input, the variable attenuator 16 is controlled by the error output, and the ramping waveform control is performed by the negative feedback. In this embodiment, the waveform of the reference ramp signal 25 is changed according to the power level. After the ramp period, the switch 23 is switched to the movable-side terminals a and d, respectively, and the detection voltage having a long time constant that has passed through the low-pass filters 20 and 22 is respectively supplied to the negative side and the positive side of the comparison error amplifier 24. Since the variable attenuator 16 is input and negatively feedback-controlled, the power amplifier 17 functions as an amplifier with a constant gain, and the transmission output is stabilized in accordance with the level of the transmission modulation wave generator 14 driven by a constant voltage power supply. Increase or decrease.

High-speed control is not required after the output rises, and what is required is an increase / decrease in output level. This is performed by the level variable amplifier 13 before the power amplifier 17, so that the power amplifier 17 It only has to work as a constant gain amplifier. Therefore, in the present embodiment, the negative feedback loop is operated so as to work as a constant gain even if the power supply voltage changes, the frequency changes, the operation bias condition is changed, etc. In order to reduce, when performing the current control according to the output level,
Even if the gain of the power amplifier 17 changes, the constant gain is maintained in the entire system, so that the current consumption can be positively reduced.

(Embodiment 2) FIG. 2 shows the configuration of a second embodiment of the present invention, which is different from the first embodiment shown in FIG. 1 in that the variable attenuator 16 is changed to a variable gain amplifier 27. The only difference is that As described above, by using the variable gain amplifier instead of the variable amplifier as the level variable element in front of the power amplifier 17, there is an advantage that the load of the gain of the power amplifier 17 can be reduced.

(Embodiment 3) FIG. 3 shows the configuration of the third embodiment of the present invention. In contrast to the first embodiment shown in FIG. 1, the level variable amplifier 13 in the transmission modulation generator 14 is used as an amplifier. 13A and the variable attenuator 13B, the variable attenuators 28 and 30 and the amplifier 2 are provided in front of the first diode detector 19 and the second diode detector 21, respectively.
Insert a circuit in which 9 and 31 are connected in series, and insert each variable attenuator 1
The control unit 32 adjusts the levels of 3B, 28, and 30.

In the first and second embodiments, since the detection range of the diode detectors 19 and 21 is 20 dB, the transmission output is strictly controlled by the negative feedback loop from the maximum output to the minus. It is in the range of 20 dB. Therefore, in order to expand this range, the attenuators 28 and 30 and the linear amplifiers 29 and 31 are connected to the diode detectors 19 and 2, respectively.
Insert before 1. In this case, it is necessary to control the attenuation amount so that it has the characteristics that are exactly opposite to those of the variable attenuator 13B of the transmission modulated wave generator 14. For example, when increasing the output by 0.5 dB, the attenuation amount of the variable attenuator 13B is decreased by 0.5 dB and the amount input to the distributor 15 is increased by 0.5 dB. On the other hand, the variable attenuators 28 and 30 connected to the diode detectors 19 and 21 are controlled so that the attenuation amount increases by 0.5 dB, so that the diode detector 1 is eventually
A substantially constant level is input to 9 and 21.

As described above, in this embodiment, the system including the power amplifier 17 is maintained at a constant gain over a very wide range of the transmission output, and stable output control is possible. However, in this embodiment, the reference waveform of the transmission ramping is constant without depending on the output.

As described above, according to the above embodiments, the CDM
It is possible to control the transmission output during continuous transmission, which is peculiar to the A system, in a wide dynamic range, and to compensate for fluctuations in power supply voltage when using a battery power supply, temperature fluctuations due to environmental changes, etc., thus reducing current consumption. Can be achieved.

[0018]

As is apparent from the above-described embodiments, the present invention enables power control during continuous transmission output peculiar to the CDMA system over a wide dynamic range, and also allows control of the burst output waveform. . Further, since the gain of the power amplifier can be kept constant even if the power supply voltage fluctuates, the frequency fluctuates, or the bias condition is changed, it is possible to stabilize the output and reduce the current consumption. Have.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a transmission output control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a transmission output control device according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a transmission output control device according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a transmission output control device in a conventional example.

[Explanation of symbols]

 Reference Signs List 11 oscillator 12 modulator 13 level variable amplifier 13A, 29, 31 amplifier 13B, 28, 30 variable attenuator 14 transmission modulated wave generator 15 distributor 16 variable attenuator 17 power amplifier 18 directional coupler 19 first diode Detector 20 First low-pass filter 21 Second diode detector 22 Second low-pass filter 23 Switch 24 Comparison error amplifier 25 Reference ramp signal 26 Ramp timing signal 27 Gain variable amplifier 32 Control section

Claims (9)

[Claims] 1. A transmission modulated wave generating section, a distributor connected to the output side of the transmission modulated wave generating section, and a power amplifier connected to one output side of the distributor via a level variable element. A directional coupler connected to the output side of the power amplifier, a first diode detector and a first low-pass filter connected in series to the output side of the directional coupler, and the other output of the distributor A second diode detector and a second low-pass filter connected in series on the side, switching the connection point of the first diode detector and the first low-pass filter and the output of the first low-pass filter, and the second low-pass filter. A transmission output control device including a switch for switching between a filter output and a reference signal, and a comparison error amplifier which receives the output of the switch and controls the level variable element. . 2. The transmission output control device according to claim 1, wherein the first and second low-pass filters have the same characteristics of cutoff frequencies. 3. The switch selects either of the two signal systems that have passed the first and second low pass filters or the two signal systems that do not pass the first and second low pass filters according to the ramp timing signal. The transmission output control device described. 4. The transmission output control device according to claim 1, wherein the transmission modulation wave generator is driven by a constant voltage power supply. 5. The transmission output control device according to claim 1, wherein the power amplifier is connected to a current control terminal for improving power conversion efficiency. 6. The transmission output control device according to claim 1, wherein the level variable element is a variable attenuator or a variable gain amplifier. 7. The transmission output control device according to claim 1, wherein the transmission modulation wave generator is temperature-compensated. 8. A circuit in which a variable attenuator and an amplifier are connected in series is inserted before the first and second diode detectors,
2. The transmission output control device according to claim 1, wherein the level variable amplifier before the distributor comprises an amplifier and a variable attenuator. 9. The transmission output control according to claim 8, wherein the attenuation control characteristics of the variable attenuator placed in front of each diode detector and the variable attenuator placed in front of the distributor are opposite to each other. apparatus.