Circuit for a front-end tunable filter of a communication and broadcast receiver and a tuning method thereof

US8862089B2 · kind B2 · utility

Assignee

• Beijing KT Micro, Ltd. · CN

Inventors

• Han Wang · Nanjing, CN
• Yi Yang · North Syracuse, US
• Zhen Li · Beijing, CN
• Pei Yang · Hsinchu, TW
• Dianyu Chen · Beijing, CN
• Haiqing Lin · Beijing, CN
• Yihai Xiang · Irvine, US
• Zhongzhi Liu · Beijing, CN

Key dates

• Filing date: Oct 18, 2012
• Grant date: Oct 14, 2014
• Expiry date: Dec 5, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03H2210/04
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

A circuit for a front-end tunable filter of a communication and broadcast receiver and a tuning method thereof are described herein. In one aspect, the circuit of the tunable filter may be independent of the signal reception link of the receiver. The pre-filter (104) includes a variable capacitance (146) which is adjusted by a tuning signal (160). A negative resistance element (144) and the pre-filter (104) may form an oscillator. The negative resistance element (144) is controlled by an amplitude control signal (162) outputted from an oscillation amplitude control circuit (142). The oscillation amplitude control circuit (142) stabilizes the amplitude of a radio frequency signal (130) in a preset range. An oscillation frequency control circuit (140) stabilizes the frequency of the signal (130) in a preset frequency range by a tuning signal (160). The tuning is completed until both of the amplitude and the frequency of the oscillation signal meet the preset ranges.