RF Receiving Circuit With Shared LO Path for Interference Filtering

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Solution Overview

Problem

Conventional radio frequency receivers experience excessive power consumption due to the need for additional buffers to provide local oscillation signals for both the mixer and bandpass filtering circuits, leading to interference when the received frequency does not match the operating frequency.

Innovation Solution

A radio frequency receiving circuit design that includes a first amplification circuit, an oscillation circuit, a frequency mixing and amplification circuit, and a dividing circuit, where the dividing circuit forms a dividing loop at a preset frequency using a bandpass filtering circuit and control circuit, allowing selective activation to cancel out interfering frequencies without the need for two separate buffers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If two buffers are used to provide local oscillation signals for the mixer and bandpass filtering circuits, then the interference filtering function is achieved, but the power consumption increases excessively

Engineering Contradiction:

ImproveinterferenceVSAvoidpower consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent merges the local oscillation signal generation for the bandpass filtering circuit with the existing local oscillation source circuit that provides signals to the mixer. By sharing the same local oscillation source and using the amplifier's output signal to drive the bandpass filtering circuit, the design eliminates the need for a separate buffer, thereby reducing power consumption while maintaining interference filtering capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The local oscillation source circuit is designed to serve multiple functions: it provides the local oscillation signal to the mixer for frequency conversion and simultaneously provides the drive signal to the bandpass filtering circuit through the amplifier. This multi-functional design allows a single circuit to fulfill multiple roles, avoiding the need for additional dedicated buffers and reducing overall power consumption.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If a bandpass filtering circuit is added to cancel interference, then the frequency selectivity is improved, but the device complexity increases due to additional components

Engineering Contradiction:

Improvefrequency selectivityVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The bandpass filtering circuit is integrated into the existing signal path by utilizing the amplifier's output signal to drive the filtering circuit, which then feeds into the mixer. This merging approach allows the filtering function to be added without requiring completely separate signal paths or additional independent control circuits, thereby reducing the overall device complexity while improving frequency selectivity.

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 design reduces power consumption by eliminating the need for two buffers, enabling efficient frequency filtering and minimizing interference while maintaining effective signal processing.

Implementation Method 1

an oscillation circuit, a frequency mixing and amplification circuit... The oscillation circuit is configured to provide a local oscillation signal

Methodology Applied

Scientific EffectElectromagnetic oscillation: Electromagnetic Induction

Implementation Method 2

The frequency mixing and amplification circuit is coupled to the first amplification circuit and configured to perform frequency mixing and amplification on the amplified input signal according to the local oscillation signal

Methodology Applied

Scientific EffectFrequency mixing: Heterodyne

Implementation Method 3

The dividing circuit comprises a bandpass filtering circuit and a control circuit... the bandpass filtering circuit forms the dividing loop for the amplified input signal at the preset frequency

Methodology Applied

Scientific EffectBandpass filtering: Filter (electronic)

Data Source

PatentUS20240235597A9Radio frequency receiving circuit and chip comprising the same

Publication Date: 2024.07.11 REALTEK SEMICON CORP

AI summary

A radio frequency receiving circuit includes a first amplification circuit, an oscillation circuit, a frequency mixing and amplification circuit and a dividing circuit. The first amplification circuit is configured to amplify an input signal so as to generate an amplified input signal. The oscillation circuit is configured to provide a local oscillation signal. The frequency mixing and amplification circuit is configured to mix and amplify the amplified input signal according to the local oscillation signal. The dividing circuit is configured to form a dividing loop at a preset frequency for the amplified input signal according to the local oscillation signal when the dividing circuit is driven. A chip including the radio frequency receiving circuit and a main circuit is also provided. The main circuit is configured to drive the dividing circuit when the second input signal is determined to include a signal of the preset frequency.