JPS6019310A - High frequency power control circuit - Google Patents

Abstract

PURPOSE:To attain the control of high frequency power with high accuracy by applying cascade connection to PIN diodes to a power amplifier, controlling the attenuation of the 1st PIN diode in response to ambient temperature and controlling the attenuation of the 2nd PIN diode through the output of a detector from the amplifier output. CONSTITUTION:A high frequency signal entering an input terminal 1 in amplified by amplifiers 2 and 3, applied to attenuators 4, 5 comprising PIN diodes, amplified further by amplifiers 6, 7 and outputted from an output terminal 8. Further, a part of an output power is extracted from the amplifier 7, converted into a DC voltage by a detection circuit 9, and then compared with an output voltage of a reference voltage generating circuit 11 by an operational amplifer circuit 10, applied to the attenuator 5 and the part of power is activated in a direction so as to make an output power constant by controlling the attenuation. Further, a temperature detecting circuit 12 outputting a different voltage in response to the change in ambient temperature and a control voltage generating circuit 13 outputting a control voltage through the reception of the output of the circuit 12 are connected to the attenuator 4. The erroneous component not controlled by the attenuator 4 is compensated and the output power is kept constant by extracting a part of the output from the amplifier 7 and controlling the attenuation of the attenuator 5 through the output. Further, neither surplus nor deficiency of output power is produced to an intermittent wave.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency power control circuit that stabilizes the output power of a high frequency power amplifier used in a transmitting device of a satellite communication ground station.

In a microwave or sub-millimeter wave band transmitting device, a high frequency power control circuit is used to reduce fluctuations in the high frequency output of a high frequency power amplifier due to fluctuations in ambient power. Conventional high-frequency power control circuits extract a part of the output of a high-frequency power amplifier, detect it, and convert it to a DC voltage, and then combine it with a high-frequency product amplifier so that the DC/voltage becomes a preset reference voltage value. It consisted only of a circuit that controlled the attenuation of PIN diodes connected in cascade.

In this conventional high frequency/power control circuit, high frequency jib.

If the gain of the power amplifier is large, the gain fluctuation due to ambient temperature fluctuations will naturally be large. In order to accurately control output power, a high frequency power control circuit becomes complex. Furthermore, since the closed loop gain 1'J of the high frequency power control circuit must be large, if the signal being amplified by the high frequency iC power amplifier is not a continuous wave but a pulsed intermittent wave, the The response speed of the high-frequency power control circuit used in the high-frequency power amplifier becomes a frequent problem, and the quality of the line in which the high-frequency power amplifier is inserted deteriorates due to excessive or insufficient output power.

An object of the present invention is to provide a high frequency power control circuit that can control high frequency power with high precision.

The high-frequency power control circuit according to the present invention includes first and second PIN diodes connected in cascade to a high-frequency power amplifier, and a high-frequency power control circuit that adjusts the ambient temperature to compensate for gain fluctuations of the high-frequency power amplifier due to ambient temperature. a circuit that controls the amount of attenuation of the tenth PIN diode according to;
A detector that detects a part of the output of the high-frequency power amplifier, and a circuit that controls the amount of attenuation of the second I) I N diode in a direction in which the output of the detector approaches a predetermined reference value. It consists of

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. A high frequency signal input to input terminal 1 is amplified by amplifier 2 and amplifier 3, applied to attenuators 4 and 5 using PIN diodes, further amplified by amplifiers 6 and 7, and output from output terminal 8. A part of the output power is taken out from the amplifier 7 and converted into a DC voltage by the detection circuit 9, and then compared with the output voltage of the reference voltage generation circuit 11 by the operational amplifier circuit 10 and added to the attenuator 5. , which acts in the direction of controlling the amount of attenuation and making the output power constant 6 Furthermore, the attenuator 4 includes a temperature detection circuit 12 that outputs different voltages in response to changes in ambient temperature; A control voltage generation circuit 13 that outputs a control voltage is connected.

The amount of attenuation of the attenuator 4 is determined by the detection circuit 9. When operational amplifier circuit IO and attenuator 5 are not connected, amplifier 2. 3
．． The control voltage generation circuit 13 presets most of the expected gain fluctuations due to changes in the ambient temperature that occur in 6 and 7 so that the temperature can be compensated for. Therefore, by attenuator 5? Even in the absence of an It control circuit, the amplifier 2. 3. 6. The overall output power fluctuation of 7 is sufficiently small compared to the case without control using attenuator 4. However, control using only attenuator 4 can accurately control the output power due to the non-uniformity of the temperature gain of the amplifier, etc. It is difficult to keep constant. Therefore, as described above, a part of the output is taken out from the amplifier 7, and the amount of attenuation of the attenuator 5 is controlled by this output to keep the output power constant without compensating for the error that could not be fully controlled by the attenuator 4.

According to this embodiment, the dynamic range of the attenuator 5 is sufficient to compensate for the above-mentioned error, so the control circuit becomes very simple. Furthermore, even when transmitting an intermittent wave, since the dynamic range of the attenuator 5 is narrow, the above-mentioned problem of output power fluctuation or shortage at the rise of a pulse is virtually eliminated.

As explained above, according to the present invention, a high frequency power control circuit that can control high frequency power with high accuracy can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. 1...Input terminal, 2.3.6.7...
Amplifier, 4゜5...PIN diode attenuator,
8... Output terminal, 9... Detection circuit, 1
0... operational amplifier circuit, 11... reference voltage generation circuit, 12... temperature detection circuit. 13... Control voltage generation circuit. Plate ゛Representative Patent Attorney yKF+1,ノ

Claims (1)

[Scope of Claims] First and 20th PIN diodes each connected in cascade to a high frequency power amplifier, and a 10th PIN diode that is connected in accordance with the ambient temperature in a direction to compensate for gain fluctuations of the high frequency power amplifier due to ambient temperature. a circuit for controlling the amount of attenuation of the high-frequency power amplifier; and a detector for detecting a part of the output of the high-frequency product amplifier. and a circuit for controlling the amount of attenuation of the 20th PIN diode in a direction in which the detector output approaches a predetermined reference value.