Invention Grant
- Patent Title: Tuner circuit and digital broadcast receiver with low distortion performance and low power consumption
- Patent Title (中): 调谐器电路和数字广播接收机具有低失真性能和低功耗
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Application No.: US11515474Application Date: 2006-09-05
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Publication No.: US07956933B2Publication Date: 2011-06-07
- Inventor: Kohji Ohiwa
- Applicant: Kohji Ohiwa
- Applicant Address: JP Osaka
- Assignee: Sharp Kabushiki Kaisha
- Current Assignee: Sharp Kabushiki Kaisha
- Current Assignee Address: JP Osaka
- Agency: Birch, Stewart, Kolasch & Birch, LLP
- Priority: JP2005-257876 20050906
- Main IPC: H04N5/50
- IPC: H04N5/50 ; H04N5/44

Abstract:
In a tuner circuit, an automatic gain control circuit generates an RF-AGC voltage for automatically controlling a gain of an RF-AGC amplifier in accordance with a level of a signal output from an IF amplifier. An emitter follower circuit includes a transistor for current amplification, and varies a drive current of the transistor in accordance with the RF-AGC voltage. Thus, when an interference signal is at a high level, the drive current of the transistor becomes large. Therefore, distortion performance of the emitter follower circuit is improved. On the other hand, in a normal state where the interference signal is at a low level, the drive current of the transistor fails to become large. Therefore, low power consumption is achieved.
Public/Granted literature
- US20070052867A1 Tuner circuit and digital broadcast receiver with low distortion performance and low power consumption Public/Granted day:2007-03-08
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