Negative Impedance Receiver Circuit With Capacitive Linearity Control
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Solution Overview
Problem
Conventional negative impedance circuits in receivers suffer from poor linearity, leading to significant interference from out-of-band noise, which affects the performance of the receiver.
Innovation Solution
A signal processing circuit with a negative impedance circuit that includes capacitors with different DC voltage levels, reducing the impedance-signal variation rate and enhancing linearity by using transistors and capacitors to amplify signals while maintaining stable voltage differences across terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional negative impedance circuit is used to amplify signals, then signal gain is improved, but linearity deteriorates causing out-of-band noise interference
Solution Approach 1:
The negative impedance circuit is segmented into multiple parallel paths, each containing a transistor and capacitor combination. This segmentation allows the circuit to achieve signal amplification while distributing the impedance variation across multiple paths, thereby improving linearity and reducing out-of-band noise interference.
Solution Approach 2:
The invention changes the electrical parameters of the circuit by introducing capacitors with specific capacitance values in parallel with transistors. This parameter modification enables the circuit to maintain negative impedance characteristics for signal amplification while controlling impedance variation to improve linearity and reduce noise interference.
2Measurement precision
If signal amplification is increased to handle weak in-band signals, then sensitivity is improved, but impedance variation increases causing non-linearity
Solution Approach 1:
The circuit is divided into multiple parallel amplification paths, each with controlled impedance characteristics. This segmentation allows the overall circuit to achieve high signal sensitivity while each individual path maintains stable impedance, thereby reducing non-linearity effects.
Solution Approach 2:
Capacitors are introduced as intermediary elements between the transistors and ground reference. These capacitors act as mediators that stabilize the impedance seen by the signal while allowing the transistors to provide the necessary signal amplification for handling weak in-band signals.
Data Source
AI summary
A signal processing circuit includes a signal receiving circuit for generating a first input signal and a second input signal; a signal output circuit for generating a first output signal and a second output signal according to the first input signal and the second input signal; a negative impedance circuit, for amplifying the first input signal at the first input terminal to generate a first amplified input signal at the second output terminal, and for amplifying the second input signal at the second input terminal to generate a second amplified input signal at the first output terminal; a first capacitor; a second capacitor; wherein the first capacitor and the second capacitor have different DC voltage levels at both terminals, such that the impedance-signal variation rate of the negative impedance circuit is lower than a predetermined level.