JPH0918247A - High frequency amplifier device - Google Patents

Abstract

PURPOSE: To linearly amplify a digital signal with high efficiency for adjustment of a limited-band phase, etc., by controlling the output level of an amplifier circuit by means of an envelope signal. CONSTITUTION: The modulated wave inputted from an input terminal 9 is inputted to an amplifier means 5 and amplified there after undergoing the adjustment of its phase via a phase adjustment means 3. At the same time, the input modulated wave is also supplied to an envelope signal detection means 2 via the means 1 which detects an envelope signal out of the modulated wave and inputs it to a control voltage generation means 6. The envelope signal inputted to the means 6 is converted into a digital signal by an A/D conversion means 6a, and the output control voltage is generated by a D/A conversion means 6c via a storage means 6b and inputted to the means 5. The output control voltage is applied to a gate G of a gate-grounded FET 5c. Then the distribution of drain bias given from a DC power supply 4 of a grounded-source FET 5b and the FET 5c is changed, and the output of the means 5 is controlled according to the envelope signal. Thus the digital signal can be linearly amplified with high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency amplifier used in a high frequency communication device, and more particularly to a high frequency amplifier for high frequency amplification of a band-limited digital signal.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing the structure of a conventional high frequency amplifier. In the figure, 101 is a signal distributing means, 102 is an envelope signal detecting means, 104 is a DC power source for drain bias, 105 is an amplifying means, 105a is an input circuit, 105b is a source grounded FET, 105d is an output circuit, and 106 is non-linear. A control circuit, 108 is a DC voltage and current converting means, 109 is an input terminal, and 110 is an output terminal.

Next, the operation of the conventional high frequency amplifier shown in FIG. 7 will be described. In order to control the output of the amplification means 105, the drain bias of the source-grounded FET 105b is changed. In order to control the drain bias in this way, a DC voltage and current converting means capable of supplying a large current and having a variable output is required. For this reason, overall efficiency did not become a major improvement measure. For example, there is an output variable DC-DC converter as the DC voltage and current converting means, but the efficiency of the amplifier is 50%, and the output variable DC-DC converter is
The power conversion efficiency of the DC converter is 70%, and even if both of them are highly efficient, the total efficiency is 35%.

Further, the DC-DC converter requires hybrid parts such as a transformer and a capacitor, which has been an obstacle to miniaturization.

FIG. 8 shows the structure of another conventional high-frequency amplifier for overcoming this problem. In FIG.
1 is signal distribution means, 202 is envelope signal detection means, 20
4 is a DC power supply for drain bias, 205 is an amplifying means,
205a is an input circuit, 205b is a common source FET, 2
05c is a grounded-gate FET, 205d is an output circuit, 20
6 is a level converting means, 209 is an input terminal, and 210 is an output terminal. Then, the output of the level converting means 206 is given to the gate of the gate-grounded FET 205c to supply the source-grounded F
The output level of the amplifying means 205 is controlled by changing the bias distribution between the ET 205b and the grounded-gate FET 205c. Therefore, the output control signal need only be the voltage, and the DC voltage and current conversion means could be eliminated.

FIG. 9 shows a characteristic example of the control voltage necessary for performing the above output control. Further, FIG. 10 shows a characteristic example of the envelope signal output from the envelope signal detecting means. In order to control this amplifier linearly, the envelope signal should be 10 mV.
It is necessary to convert to the control voltage level with the following accuracy. Therefore, sufficient linearity has not been obtained.

Further, since there is a time difference between the time when the output control signal is supplied to the amplifying means and the time when the modulated wave to be amplified is supplied to the amplifying means, the linearity is deteriorated.

[0008]

However, in the first conventional high frequency amplifying apparatus, in order to control the output of the amplifying means, a large current can be supplied and a variable output DC voltage and current converting means is required. Become. For this reason, overall efficiency did not become a major improvement measure. Further, in the second conventional high frequency amplifying device, the output of the amplifying means can be controlled without using the DC voltage and current converting means, but its linearity is not sufficient.

The present invention is intended to solve these problems, and is capable of linearly amplifying a digital signal such as band-limited phase modulation with high efficiency and reducing the call time of a digital portable device. It is an object of the present invention to provide a high frequency amplification device that can be extended.

[0010]

In order to solve the above problems, the present invention provides a signal distribution means for distributing high frequency waves and a phase adjusting means for adjusting the phase of one modulated wave distributed by the signal distribution means. An amplifying means that uses the phase-adjusted modulated wave as an input signal, an envelope signal detecting means that detects an envelope signal of the other modulating wave distributed by the signal distributing means, and an envelope signal detecting means. An analog-to-digital conversion means for converting the detected envelope signal into a digital signal, a digital-to-digital converter for converting the digital signal into an analog voltage.
The control circuit includes analog conversion means and control voltage generation means including storage means that connects the analog-digital conversion means and the digital-analog conversion means.
It is characterized in that the drain terminal of the source-grounded FET and the source terminal of the gate-grounded FET are directly connected to each other by an amplification circuit including a cascode amplification element.

Further, the phase adjustment means is installed immediately before the envelope signal detection means, or immediately before or after the storage means, and immediately before or after the control voltage generation means, so that the phase adjustment is performed by an analog signal. Instead of performing it on a certain modulated wave, it is performed on the input signal or output signal of the storage means which is a digital signal.

[0012]

According to the present invention having such a configuration, the output of the control voltage generating means is applied to the gate of the gate-grounded FET to supply the source-grounded FET and the gate-grounded FE.
By changing the bias distribution of T, the output level of the amplifier circuit is controlled according to the envelope signal.

Therefore, in the high frequency amplifying apparatus of the present invention, the control voltage is generated by the control voltage generating means instead of obtaining the control voltage by level conversion, so that the output control can be performed with higher accuracy than in the past. . Further, the time difference between the time when the output control signal is supplied to the amplifying means and the time when the modulated wave to be amplified is supplied to the amplifying means is eliminated by the phase adjusting means, and further linearization is achieved. did.

Therefore, the present invention can solve the above-mentioned problems, can highly efficiently and linearly amplify a band-limited digital signal such as phase modulation, and can extend the talk time of a digital portable device. It is possible to provide a high-frequency amplification device that becomes

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention. In this embodiment, a signal distribution unit 1, an envelope signal detection unit 2, a phase adjustment unit 3, a DC power supply 4, and a control voltage generation unit including an analog-digital conversion unit 6a, a storage unit 6b, and a digital-analog conversion unit 6c. 6, and the input circuit 5a and the output circuit 5 using a cascode amplifier element in which the drain terminal of the source-grounded FET 5b and the source terminal of the gate-grounded FET 5c are directly connected to each other.
It is composed of amplification means 5 having d.

In the figure, 9 is an input terminal and 10 is
Indicates an output terminal. The signal distribution unit 1 has a function of distributing the modulated wave, and can distribute the signal by capacitive coupling with a capacitor by a simple method.

Next, the operation of the apparatus shown in this embodiment will be described. The DC power supply 4 supplies a drain bias to the amplification means 5. The modulated wave input from the input terminal 9 is
The phase is adjusted by the phase adjusting means 3 and then input to the amplifying means 5 and amplified. At this time, a part of the modulated wave is supplied to the envelope signal detecting means 2 by the signal distributing means 1 before being input to the phase adjusting means 3. Envelope signal detection means 2
Then, the envelope signal is detected from the supplied modulated wave. The control voltage generation means 6 generates an output control voltage according to the input envelope signal. The amplifying means 5 controls the output by the output control voltage and operates as a highly efficient and linear amplifying device.

The operation of the control voltage generating means 6 is as follows. The envelope signal is converted into a digital signal by the analog-digital conversion means 6a. Storage means 6
b sends a digital signal to the digital-analog conversion means 6c according to the signal supplied from the analog-digital conversion means 6a. Digital-analog conversion means 6c generates an output control voltage according to the signal received from storage means 6b.

FIG. 2 is a block diagram showing the configuration of the second embodiment of the present invention. In this embodiment, the phase adjusting means 3 is arranged immediately before the envelope voltage detecting means 2 instead of immediately before the control voltage generating means 6 in the first embodiment. As a result, the phase adjustment is performed by placing the control system path instead of the main signal path.

FIG. 3 is a block diagram showing the configuration of the third embodiment of the present invention. In this embodiment, the phase adjusting means 3 is replaced with the phase adjusting means 33 in the first embodiment. By this, the phase is adjusted digitally.

FIG. 4 is a block diagram showing the configuration of the fourth embodiment of the present invention. In this embodiment, the phase adjusting means 3 is replaced with the phase adjusting means 43 in the first embodiment. As a result, phase adjustment is performed at the envelope signal frequency.

Here, when the gate bias Vc of the grounded-gate FET of the cascode amplification element is changed and the saturation output is changed by this, the A formed by the amplification element concerned is changed.
An example of changes in the output and efficiency of the class B amplifier is shown by a thin line in FIG. 5, and an example of characteristics of the output and efficiency of the amplifier of each of the present embodiments is shown by a thick line in FIG. As can be seen from the figure, the amplifier of each of the present embodiments operates linearly even in the high efficiency region.

An example of the spectrum of the output signal of the class AB amplifier composed of the cascode amplifying element is shown in FIG. 6 (a).
Further, an example of the spectrum of the output signal of the amplifier of each embodiment is shown as (b) in FIG. (B) is (a)
It can be confirmed that the suppression ratio of the side lobe is large as compared with.

[0024]

As described above, according to the present invention,
It is possible to amplify a band-limited digital signal such as phase modulation with high efficiency and linearly, and it is possible to extend the call time of a digital portable device.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a third exemplary embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a fourth embodiment of the present invention.

FIG. 5 is a diagram showing an example of control voltage dependence of output and efficiency of a class AB amplifier using a cascode amplifying element and output and efficiency characteristics of an amplifier according to the present invention.

FIG. 6 is a diagram showing an example of a spectrum of an output signal when a modulated wave is amplified by a class AB amplifier using a cascode amplification element and an example of a spectrum of an output signal of the present amplifier at the same operating point as the amplifier.

FIG. 7 is a block diagram showing a conventional high frequency amplifier.

FIG. 8 is a block diagram showing another conventional high frequency amplifier.

FIG. 9 is a diagram showing an example of an output control voltage required for linearly controlling an amplifier.

FIG. 10 is a diagram showing an example of an envelope signal output from an envelope signal detecting means.

[Explanation of symbols]

 1, 101, 201 Signal distribution means 2, 102, 202 Envelope signal detection means 3, 33, 43 Phase adjustment means 4, 104, 204 DC power supply 5, 105, 205 Amplification means 5a, 105a, 205a Input circuit 5b, 5c , 105b, 205b, 205c FETs 5d, 105d, 205d Output circuit 6 Control voltage generation means 6a Analog-digital conversion means 6b Storage means 6c Digital-analog conversion means 9, 109, 209 Input terminal 10, 110, 210 Output terminal 106 Non-linear Control circuit 108 DC voltage and current conversion means 206 Level conversion means

Claims (4)

[Claims] 1. A signal distribution means for distributing a high frequency wave, a phase adjustment means for adjusting the phase of one of the modulated waves distributed by the signal distribution means, and an amplification means for using the phase adjusted modulated wave as an input signal. An envelope signal detecting means for detecting an envelope signal of the other modulated wave distributed by the signal distributing means, and an analog-digital converting means for converting the envelope signal detected by the envelope signal detecting means into a digital signal. A digital-analog conversion means for converting a digital signal into an analog voltage, and a control voltage generation means composed of a storage means connecting the analog-digital conversion means and the digital-analog conversion means. An amplifier circuit consisting of a cascode amplifier element in which the drain terminal of the FET and the source terminal of the gate-grounded FET are directly connected to each other. The output of the control voltage generation means is applied to the gate of the common-gate FET to change the bias distribution of the common-source FET and the common-gate FET, thereby changing the output level of the amplifier circuit according to the envelope signal. A high frequency amplifying device characterized by being controlled. 2. The phase adjusting means is installed immediately before the envelope signal detecting means, and one of the modulated waves distributed by the signal distributing means is used as an input of the envelope signal detecting means.
The high frequency amplifying device according to claim 1, wherein the other modulating wave distributed by the signal distributing means is input to the amplifying means. 3. The phase adjusting means is provided immediately before or after the storage means, and one modulated wave distributed by the signal distributing means is used as an input of the envelope signal detecting means, and by the signal distributing means. The high frequency amplifier according to claim 1, wherein the other distributed modulated wave is input to the amplifying means. 4. The phase adjusting means is installed immediately before or after the control voltage generating means, and one modulated wave distributed by the signal distributing means is used as an input of the envelope signal detecting means, and the signal distributing The high frequency amplifier according to claim 1, wherein the other modulated wave distributed by the means is input to the amplifying means.