JP2002043873A - Wideband power amplifier circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide satisfactory amplification efficiency or to suppress generation/amplification of unwanted higher harmonic waves (especially of secondary higher harmonic waves), for reducing power consumption, and moreover to deal with frequency hopping. SOLUTION: By locating band-pass filters B1, D1, B2, D2, B3 and D3, although power amplifiers C1, C2 and C3 are respectively configured as narrow-band power amplifiers 1, 2 and 3, as to which one of power amplifiers C1, C2 and C3 is to amplify a VHF band signal, the gain in each of power amplifiers C1, C2 and C3 is controlled by a bias voltage controller F, so that only the power amplifier corresponding to a transmitter output frequency can be set in an amplified operating state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide band power amplifier, and more particularly to a wide band power amplifier suitable for frequency hopping in a VHF band.

[0002]

2. Description of the Related Art Heretofore, in order to amplify a VHF band signal in a wide band, a power amplifier circuit is actually configured as one wide band amplifier.

[0003]

However, in this case, if the frequency characteristic is designed to be flat, the amplification efficiency is not good, and not only a high-speed tuner and a high-speed switch are required. In addition, unnecessary harmonics (especially second harmonics) due to wide band amplification are VHF.
There is a problem that it is generated and amplified together within the band.

[0004] An object of the present invention is to improve the amplification efficiency when a VHF band signal is flatly amplified in a wide band, and not only does a high-speed tuner and a high-speed switch become unnecessary, but also unnecessary harmonics ( In particular, generation of second harmonic)
It is an object of the present invention to provide a broadband power amplifier circuit whose amplification can be suppressed.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a plurality of power amplifiers and a corresponding frequency amplifier before and after each of the power amplifiers so that the frequency amplification characteristics of each of the power amplifiers are arranged adjacent to each other as a whole. A band-pass filter arranged according to the amplification characteristic and a V
A distributor for distributing the HF band signal to each of the preceding band-pass filters, a combiner for combining the outputs from the respective subsequent band-pass filters, and a power amplifier corresponding to a transmitter output frequency among the plurality of power amplifiers In order to keep only the amplifying operation state, a bias voltage controller that performs gain control by a bias voltage is achieved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a schematic configuration of an example of a broadband power amplifier circuit according to the present invention.
As shown, in this example, three power amplifiers (for example, configured as power transistors) C ₁ , C ₂ , C ₃
And these power amplifiers C
Bandpass filters B ₁ , D ₁ , B ₂ , D ₂ , B ₃ , and D ₃ in predetermined passbands for defining the frequency amplification characteristics are also arranged before and after each of C ₁ , C ₂ , and C _3. It has become. After all, the band pass filters B ₁ , D
₁ , B ₂ , D ₂ , B ₃ , and D ₃ are arranged so that each of the power amplifiers C ₁ , C ₂ , and C ₃ is configured as a narrow-band power amplifier. The amplification characteristic is, as shown in FIG.
_1, C _2, C _3, respectively _{(f0 ~f 1), (f} 1 ~f
_2), in which are configured as having a frequency amplification characteristics of (f ₂ ~f _3).

An arbitrary VHF band signal to be amplified is divided by a divider A, a pre-stage band-pass filter B ₁ , B ₂ , B
Power through the _third amplifier C _1, C _2, while given in C _3, the power amplifier C _1, C _2, C ₃ is the amplified output from each subsequent stage band-pass filter D _1, D _2, D _3,
Which is obtained through the synthesizer E,
Which of the power amplifiers C ₁ , C ₂ , and C ₃ amplifies the VHF band signal is determined by the bias voltage controller F. The gain of each of the power amplifiers C ₁ , C ₂ , and C ₃ is controlled by the bias voltage from the bias voltage controller F so that only the power amplifier corresponding to the transmitter output frequency is in the amplification operation state. is there. When only one of the power amplifiers C ₁ , C ₂ , and C ₃ is selectively put in the amplifying operation state, power consumption can be reduced.

[0008]

As described above, in the case of the first aspect, since the VHF band signal is amplified by the narrow band power amplifier, the amplification efficiency is good and unnecessary harmonics (especially, Generation and amplification of second harmonics can be suppressed, power consumption can be reduced, and a band power amplifier circuit capable of coping with frequency hopping can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an example of a broadband power amplifier circuit according to the present invention;

FIG. 2 is a diagram illustrating frequency amplification characteristics of respective power amplifiers in which bandpass filters are arranged in front and rear stages;

[Explanation of symbols]

A: distributor, B ₁ , B ₂ , B ₃ , D ₁ , D ₂ , D ₃ ... band-pass filter, C ₁ , C ₂ , C ₃ ... power amplifier, E
... Synthesizer, F ... Bias voltage controller

Claims (1)

[Claims] 1. A wide-band power amplifier circuit for a VHF band, comprising: a plurality of power amplifiers; and a power amplifier before and after each of the power amplifiers such that frequency amplification characteristics of the respective power amplifiers are arranged as a whole adjacent to each other. A band-pass filter arranged in accordance with a frequency amplification characteristic corresponding to a stage; a divider for distributing a VHF band signal to be amplified to each of the preceding band-pass filters; and an output from each of the subsequent-stage band-pass filters. A wide-band power amplifier circuit comprising: a combiner; and a bias voltage controller that performs gain control with a bias voltage so that only a power amplifier corresponding to a transmitter output frequency among the plurality of power amplifiers is in an amplification operation state.