Stereo Decoder Auto-Calibration Circuit Pilot Signal Processing

Solution Overview

Problem

Existing stereo decoders require external passive components like filter capacitors and resistors, which occupy space and increase costs, due to the need for band-pass filters and phase-locked loop circuits in pilot signal processing.

Innovation Solution

Integration of an auto-calibration circuit and a band-pass filter within the stereo decoder to generate a control signal for setting the center frequency, along with a PLL circuit that uses a voltage-controlled oscillator to produce a reference signal, eliminating the need for external components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external passive components (filter capacitors and resistors) are used in band-pass filters and PLL circuits, then the stereo decoder can process pilot signals, but the system occupies more space and increases cost

Engineering Contradiction:

Improvepilot signal processing capabilityVSAvoidsystem space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent combines multiple discrete components (filter capacitors, resistors, band-pass filters, and PLL circuits) into a single integrated circuit chip. This merging eliminates the need for external passive components, reducing both space occupation and system cost while maintaining the pilot signal processing capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated circuit performs multiple functions simultaneously: it acts as a band-pass filter to extract the pilot signal, functions as a PLL circuit for frequency synchronization, and provides de-emphasis filtering. This multi-functionality within a single chip reduces the overall component count and space requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If external passive components (filter capacitors and resistors) are used in band-pass filters and PLL circuits, then the stereo decoder can process pilot signals, but the system cost increases

Engineering Contradiction:

Improvepilot signal processing capabilityVSAvoidsystem cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple discrete components (filter capacitors, resistors, band-pass filters, and PLL circuits) into a single integrated circuit chip. This merging eliminates the need for external passive components, reducing both space occupation and system cost while maintaining the pilot signal processing capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses standard integrated circuit design techniques to replicate the functionality of discrete passive components using semiconductor fabrication processes. This allows mass production at lower costs compared to assembling discrete components.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If multiple external components are required for band-pass filter and PLL circuit, then the stereo decoder can be designed with standard circuits, but the device complexity increases

Engineering Contradiction:

Improvecircuit design flexibilityVSAvoidnumber of external components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple discrete components (filter capacitors, resistors, band-pass filters, and PLL circuits) into a single integrated circuit chip. This merging eliminates the need for external passive components, reducing both space occupation and system cost while maintaining the pilot signal processing capability.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This integration reduces system cost and space by allowing the stereo decoder to function without external passive components, improving efficiency and reducing complexity in pilot signal processing.

Implementation Method 1

The auto-calibration circuit generates a control signal. The band-pass filter generates the pilot signal by filtering the MPX signal with a center frequency set by the control signal.

Methodology Applied

Scientific EffectFrequency control:

Implementation Method 2

The band-pass filter generates the pilot signal by filtering the MPX signal with a center frequency set by the control signal.

Methodology Applied

Scientific EffectFrequency filtering: Filter (electronic)

Implementation Method 3

The PLL circuit comprises a voltage controlled oscillator for generating an oscillation frequency in response to the control signal.

Methodology Applied

Scientific EffectVoltage-controlled oscillation:

Implementation Method 4

The PLL circuit receives the square wave signal to generate the reference signal around the predetermined frequency in response to the oscillation frequency.

Methodology Applied

Scientific EffectPhase-locked loop:

Data Source

PatentUS8045717B2Stereo decoder and method for processing pilot signal

Publication Date: 2011.10.25 MEDIATEK INC

AI summary

A stereo decoder and a method therefor are provided. The stereo decoder receives a MPX signal from an FM demodulator, and comprises a first auto-calibration circuit, a band-pass filter, a second auto-calibration circuit, a slicer and a PLL circuit. The first auto-calibration circuit generates a first control signal. The band-pass filter generates the pilot signal by filtering the MPX signal with a center frequency set by the first control signal. The second auto-calibration circuit generates a second control signal. The slicer converts the pilot signal into a square wave signal. The PLL circuit comprises a voltage controlled oscillator for generating an oscillation frequency in response to the second control signal. The PLL circuit receives the square wave signal to generate the reference signal around the predetermined frequency in response to the oscillation frequency.