Front-End Filtering Frequency Selection for Communication Receiver

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Solution Overview

Problem

Conventional LC resonant front-end frequency selection methods struggle with accurately and rapidly regulating resonance frequency, especially in receivers with high intermediate frequencies or zero/low intermediate frequencies, leading to insufficient dynamic performance and limited selectivity.

Innovation Solution

A method and device for front-end filtering frequency selection that utilizes a reference oscillator working at a preset frequency related to the target frequency, allowing for accurate tuning of the front-end filtering frequency selector through a frequency synthesizing unit and a tuner LC loop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional LC resonant front-end frequency selection is used, then the receiver can process intermediate frequency signals, but the resonance frequency regulation is slow and inaccurate, especially in high intermediate frequency receivers

Engineering Contradiction:

Improvefrequency regulation accuracyVSAvoidfrequency regulation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the conventional mechanical/manual frequency regulation method with an automated digital control system. A microcontroller calculates the required capacitance value based on the target frequency and LC circuit parameters, then automatically adjusts the variable capacitor accordingly, eliminating manual intervention and achieving both speed and accuracy in frequency regulation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system implements self-service by automatically calculating and adjusting its own frequency parameters. The microcontroller continuously monitors the receiver state and autonomously regulates the resonance frequency without external control, enabling the system to adapt quickly to different frequency requirements independently.

Inventive Principle:

Principle #25Self-service

2Adaptability or versatility

If zero or low intermediate frequency is adopted for direct sampling, then digital signal processing can be applied, but conventional LC resonant front-end frequency selection becomes difficult to implement

Engineering Contradiction:

Improvecompatibility with digital samplingVSAvoidimplementation difficulty of LC resonant circuit

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent changes the operating parameters of the LC resonant circuit to be compatible with zero or low intermediate frequency architectures. By adjusting the resonant frequency parameters and combining them with digital signal processing techniques, the system maintains the advantages of analog front-end filtering while adapting to modern digital sampling requirements.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If frequency selection network with multiple filters is used, then frequency band division can be achieved, but the front-end signal bandwidth becomes too wide causing signal blocking and insufficient dynamic performance

Engineering Contradiction:

Improvefrequency band division capabilityVSAvoidsignal quality and dynamic performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary frequency selection at the front-end using the LC resonant circuit before the signal enters the main processing path. This preliminary action narrows the signal bandwidth early in the reception chain, preventing signal blocking and improving dynamic performance before subsequent processing stages.

Inventive Principle:

Principle #10Preliminary action

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 solution enables precise and rapid regulation of the resonance frequency, improving signal-to-noise ratio, dynamic range, and overall receiver performance, while avoiding frequency multiplication and allowing for continuous no-mute tuning.

Implementation Method 1

an LC resonant front-end frequency selection loop is generally used

Methodology Applied

Scientific EffectLC resonance: Resonance

Implementation Method 2

receiving an electromagnetic wave signal

Methodology Applied

Scientific EffectElectromagnetic wave reception: Electromagnetic Induction

Implementation Method 3

disposing a reference oscillator working at a preset frequency associated with a frequency to be received

Methodology Applied

Scientific EffectOscillation: Harmonic Oscillator

Implementation Method 4

a frequency synthesizing unit and a tuner LC loop

Methodology Applied

Scientific EffectFrequency synthesis:

Data Source

PatentUS12316364B2Method and device for front-end filtering frequency selection for communication receiver

Publication Date: 2025.05.27 WUHAN UNIV

AI summary

A method for front-end filtering frequency selection for a communication receiver is provided. The method includes: disposing a reference oscillator working at a preset frequency associated with a frequency to be received by the communication receiver, where the preset frequency and the frequency to be received can be accurately converted and expressed by a formula; and transmitting the frequency to be received to a front-end filtering frequency selector to realize accurate tuning. The frequency of the front-end filtering frequency selector is a required tuning frequency based on the device parameter relationship between the reference oscillator and the front-end filtering frequency selector.