发明名称 |
Amplifier circuit having common AGC to IF and RF amplifiers for use in a transmitter |
摘要 |
An amplifier circuit comprises current-variable mode variable amplifying circuits and for amplifying an IF signal and a current-constant mode variable amplifying circuit for amplifying an RF signal. I and Q signals are applied to the IF-stage variable amplifying circuits and corresponding to two stages through a QPSK modulating circuit and amplified based on an AGC voltage VAGC applied thereto. The IF signal is converted into the RF signal by a mixer, which in turn is applied to the RF-stage variable amplifying circuit where it is amplified based on the AGC voltage VAGC common to the IF stages. The linearly-varied AGC voltage VAGC is converted into an exponentially-varied control current by transistors. Thus, a gain PG [dB] of each of variable amplifying circuits is controlled linearly with the AGC voltage VAGC.
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申请公布号 |
US5926749(A) |
申请公布日期 |
1999.07.20 |
申请号 |
US19970818403 |
申请日期 |
1997.03.12 |
申请人 |
ALPS ELECTRIC CO., LTD. |
发明人 |
IGARASHI, SADAO;AOKI, KAZUHARU;URABE, SATOSHI |
分类号 |
H03G3/20;H03F1/32;H03G3/10;H03G3/30;H04B1/04;(IPC1-7):H04B1/06 |
主分类号 |
H03G3/20 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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