Audiovisual signal processing circuit and associated television signal processing method

Abstract

A television signal processing circuit includes an audio / video (AV) signal generating circuit, an intermediate frequency (IF) mixer, a first filter, a radio-frequency (RF) mixer, a second filter and a digital-to-analog converter (DAC). The AV signal generator generates a digital AV signal. The IF mixer converts the digital AV signal to an IF AV signal. The first filter filters the IF AV signal to generate a filtered IF AV signal. The RF mixer converts the filtered IF AV signal to an RF AV signal. The second filter filters the RF AV signal to generate a filtered RF AV signal. The DAC converts the filtered RF AV signal to an analog AV signal and transmits the analog AV signal to an antenna.

Description

[0001]This application claims the benefit of Taiwan application Serial No. 105123148, filed Jul. 22, 2016, the subject matter of which is incorporated herein by reference.BACKGROUND OF THE INVENTIONField of the Invention[0002]The invention relates in general to signal processing, and more particularly to a television processing circuit applied to a set-up box (STB) and an associated television signal processing method.Description of the Related Art[0003]Demands of common households on set-up boxes (STBs) increase along with the broadcasting of digital televisions. As some older televisions are not equipped with audio / video (AV) ports for connecting to the STB, the STB needs an additional set of circuit designed for transmitting (AV) signals to these older televisions. In a conventional solution, a digital AV signal is converted to an analog signal, which is then processed and transmitted. Therefore, a more complex circuit design is required. For example, a surface acoustic wave (SAW...

AI Technical Summary

Benefits of technology

The present invention provides a television signal processing circuit in a set-up box (STB) that includes filters and signal processing circuits that are designed to be more efficient and effective. The circuit generates a digital AV signal, filters it to produce a filtered IF AV signal, mixes it with an RF signal to create a filtered RF AV signal, and then converts it to an analog format for transmission. This results in a better quality television signal that can be transmitted over a network.

Problems solved by technology

Therefore, a more complex circuit design is required.

For example, a surface acoustic wave (SAW) filter needs to be designed to filter out analog radio-frequency (RF) signals, in a way that production complications and costs are increased.

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