Output control circuit for transmission power amplifying circuit

• US 5,784,689 A
• Filed: 12/26/1995
• Issued: 07/21/1998
• Est. Priority Date: 12/30/1994
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kobayashi, Takeshi
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US08/576,966
• Time in Patent Office: 938 Days
• Field of Search: 455/126, 455/127, 330/137, 330/279, 330/129, 330/138, 330/133, 330/134, 330/285
• US Class Current: 455/126
• CPC Class Codes: H03G 3/3047 for intermittent signals, e.g. burst signals

Abstract

A higher output of two outputs from a trapezoidal wave generating circuit 4 and a pulse generating circuit 5 is produced. The control voltage signal is formed by combining the trapezoidal wave signal and the pulse signal. Sharp rising and falling edges of the pulse voltage are selected for controlling the transmission power amplifying circuit 1 in a voltage range below a predetermined voltage level, whereas gentle rising and falling edges of the trapezoidal wave signal are used for controlling the circuit 1 in a voltage range above that voltage level.

Claims

1. An output control circuit for a transmission power amplifying circuit for amplifying the power of an input signal in response to a control signal waveform comprising:

a trapezoidal wave generating circuit for generating a trapezoidal wave signal having rising and falling edges with longer rise and fall times, respectively. than those of a burst signal;

a pulse generating circuit for generating a pulse signal having a sharp rising edge in synchronization with corresponding rising edge of the burst signal and a sharp falling edge of the burst signal;

an adder for producing a reference signal comprising either the trapezoidal wave signal or the pulse signal, whichever has a higher voltage level; and

a comparator for producing a control signal which is the difference between said reference signal and a detector signal corresponding to an output of the transmission power amplifying circuit.

2. The output control circuit as set forth in claim 1, wherein the pulse generating circuit generates a pulse signal having a voltage level lower than that of a corresponding trapezoidal wave signal generated by the trapezoidal wave generating circuit.

3. The output control circuit as set forth in claim 1, wherein a low-pass filter for removing high frequency components from the trapezoidal wave signal is connected to the output of the trapezoidal wave generating circuit.

4. The output control circuit as set forth in claim 2, wherein a low-pass filter for removing high frequency components from the trapezoidal wave signal is connected to the output of the trapezoidal wave generating circuit.

5. The output control circuit as set forth in claim 1, further comprising a detector for generating said detector signal in response to detecting an output of the transmission power amplifying circuit.

6. The output control circuit as set forth in claims 3, further comprising a detector for detecting an output of the transmission power amplifying circuit and a comparator for obtaining a difference between the output of the adder to be used as a reference voltage and the output of the detector and outputting the difference as the control signal.

7. An output control circuit for a transmission power amplifying circuit for amplifying the power of an input signal in response to a control signal waveform comprising a comparator having an input reference signal and an input detector signal, said comparator generating a control signal having pulse waveform with a first rising portion, a second constant level portion, a third rising portion having a longer rise time than said first rising Portion, a fourth constant level portion, a fifth falling portion, a sixth constant level portion, and a seventh falling portion having a shorter fall time than said fifth falling portion.

8. An output control circuit for a transmission power amplifying circuit designed to amplify the power of an input burst signal in response to a control signal comprising:

a first circuit for producing a trapezoidal waveform signal waveform which rises in response to the rising of the input burst signal;

a second circuit for producing a pulse signal waveform which rises in response to the rising of the input burst signal;

a third circuit for selectively outputting a higher level output of the outputs from the first and second circuits;

a fourth circuit for detecting an output level of the transmission power amplifying circuit; and

a fifth circuit for producing a difference between the outputs of the third and fourth circuits as the control signal.

9. The output control circuit as set forth in claim 8, further comprising a low pass filter inserted between the first and third circuits.

10. The output control circuit as set forth in claim 8, wherein the second circuit is an integration circuit.