JPS61187111U - - Google Patents

Description

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本考案回路の一実施例の回路図、第２
図は従来回路の一例の回路図である。 １０……可変抵抗、１１，１２……端子、Ｃ_１
０〜Ｃ_１２……コンデンサ、Ｄ_１０〜Ｄ_１３……
ダイオード、Ｑ_１０〜Ｑ_２０……トランジスタ、
Ｒ_１０〜Ｒ_２９……抵抗。 Fig. 1 is a circuit diagram of an embodiment of the circuit of the present invention;
The figure is a circuit diagram of an example of a conventional circuit. 10...Variable resistor, 11, 12...Terminal, C _1
0 to _C12 ... Capacitor, _D10 to _D13 ...
Diode, Q ₁₀ to Q ₂₀ ...transistor,
_R10 to _R29 ...Resistance.

補正 昭６１．６．１９ 考案の名称を次のように補正する。 考案の名称 可変利得制御回路Correction June 19, 1986 The name of the invention is amended as follows. Name of invention: Variable gain control circuit

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] 差動増幅器の第１の入力端子に陰極を接続され
た第１の可変インピーダンス素子と、該第１の入
力端子に陽極を接続された第２の可変インピーダ
ンス素子と、該差動増幅器の第２の入力端子に陰
極を接続された第３の可変インピーダンス素子と
、該第２の入力端子に陽極を接続された第４のイ
ンピーダンス素子と、該第１及び第３の可変イン
ピーダンス素子の電流を可変して該第１及び第３
の可変インピーダンス素子のインピーダンスを可
変せしめる第１の電流源と、該第２及び第４の可
変インピーダンス素子の電流を可変して該第２及
び第４の可変インピーダンス素子のインピーダン
スを可変せしめる第２の電流源と、制御信号に応
じて該第１及び第２の電流源の電流量を制御する
電流制御回路とよりなり、該第１乃至第４の可変
インピーダンス素子のインピーダンスを可変して
該差動増幅器の利得を可変せしめるよう構成した
可変利得制御回路。 a first variable impedance element whose cathode is connected to a first input terminal of the differential amplifier; a second variable impedance element whose anode is connected to the first input terminal; and a second variable impedance element whose anode is connected to the first input terminal of the differential amplifier. a third variable impedance element whose cathode is connected to the input terminal thereof, a fourth impedance element whose anode is connected to the second input terminal, and the currents of the first and third variable impedance elements are varied. and the first and third
a first current source that varies the impedance of the variable impedance element; and a second current source that varies the impedance of the second and fourth variable impedance elements by varying the current of the second and fourth variable impedance elements. The current control circuit includes a current source and a current control circuit that controls the amount of current of the first and second current sources according to a control signal, and varies the impedance of the first to fourth variable impedance elements to A variable gain control circuit configured to vary the gain of an amplifier.