TV Receiver IF Isolation Circuit Against ADC Clock Harmonics
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Solution Overview
Problem
Conventional analog TV receivers face signal quality degradation and reduced signal-to-noise ratio due to clock harmonic interference from integrated analog-to-digital converters, which disrupts the operation of analog circuitry.
Innovation Solution
Incorporating an isolation circuit between the amplifier and analog-to-digital converter to prevent interference leakage, allowing the isolation circuit to pass amplified intermediate frequency signals while blocking clock harmonic interference from the ADC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an analog-to-digital converter is integrated into the analog TV receiver circuitry, then the receiver can process both analog and digital signals, but clock harmonic interference is induced from the ADC which degrades signal quality and reduces signal-to-noise ratio
Solution Approach 1:
The receiver is divided into separate analog and digital processing sections with the isolation circuit creating a boundary between them. The analog front end (including down-converter and amplifier) is segmented from the ADC and digital signal processor, allowing each section to operate independently without interfering with the other.
Solution Approach 2:
An isolation circuit is introduced as an intermediary component between the amplifier and the ADC. This intermediary circuit blocks the transmission of clock harmonic interference from the ADC to the analog signal path while still allowing the analog intermediate frequency signals to pass through to the ADC for conversion.
2Object-affected harmful factors
If an isolation circuit is added to block interference from the ADC, then signal quality is improved, but device complexity increases
Solution Approach 1:
A relatively simple isolation circuit is introduced as an intermediary component between the amplifier and the ADC. This circuit acts as a barrier to clock harmonic interference while maintaining signal integrity, providing a cost-effective solution that doesn't require complex filtering or shielding arrangements.
Data Source
AI summary
A television receiving system is disclosed, comprising an input terminal, a down-converter, an amplifier, an analog-to-digital converter (ADC), a demodulator, and an isolation circuit. The input terminal receives an RF signal. The down*converter, coupled to the input terminal, converts the RF signal to an intermediate frequency (IF) signal. The amplifier, coupled to the down-converter, amplifies the IF signal. The analog-to-digital converter, coupled to the amplifier, converts the amplified IF signal to digital data. The demodulator, coupled to the ADC, processes the digital data to generate baseband data. The isolation circuit, coupled between the amplifier and ADC, isolates the amplified IF signal from being affected by interference induced by the ADC.