Tuner and pre-circuit thereof

Abstract

The invention discloses a tuner and a pre-circuit thereof. The tuner comprises a plurality of channels, wherein at least one channel comprises a pre-filtering circuit, an amplifier and a tracking filter; the tracking filter comprises a variable capacitor and an inductor; and the variable capacitor and the inductor are coupled to an output end of the amplifier. In addition, in the tuner, at least the amplifier and the variable capacitor are arranged in a complementary metal oxide semiconductor chip. The tuner and the pre-circuit thereof have low manufacturing cost and higher filtering quality.

Description

technical field [0001] The present invention relates to a tuner, especially a tuner and its pre-stage circuit in which some or all components are fabricated on a silicon chip. Background technique [0002] In a television system, one of the functions of a tuner is to select a desired channel signal from a received broadband (broadband) television signal, and then perform subsequent signal processing on the selected channel signal. However, the currently commonly used tuner is a CAN tuner, which has a relatively large volume. In addition, the capacitor inductance filter is used in the tuner to implement the tracking filter to select the required frequency, and the capacitor in the tracking filter is a variable capacitor (varactor), however, because the signal to be processed by the tuner is Broadband (broadband) TV signals (that is, have a large frequency range), so the variable capacitor needs to have a large adjustable range, that is, a high supply voltage (about greater t...

AI Technical Summary

Problems solved by technology

However, due to cost considerations, these three pre-filter circuits are usually implemented using only a single capacitor and inductor. In this way, although the cost is reduced, there is no high filtering quality.

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