Cmos Wideband Digital Variable Gain Amplifier for Agc in Dvb-t/h Receivers *
نویسندگان
چکیده
This paper presents a novel variable gain amplifier (VGA) design which is applied in the automatic gain control (AGC) loop of DVB-T/H receivers. The VGA composed of three cascaded tunable gain stages to provide a 70 dB dynamic range with 2 dB gain steps. Each gain stage is based on a digital variable gain amplifier (DVGA) which is composed of a plurality of gain blocks (GBs) and a fully differential degeneration amplifier (FDDA). The GBs are digitally controlled current mirrors. A common-mode feedback (CMFB) circuitry is used to stabilize the FDDA by providing a stable common mode voltage. Physical measurements on silicon show that the gain error is merely 0.55 dB given a 70 dB tuning range.
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