Receiver Circuit Gain Control Without Peak Detector Capacitors
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Solution Overview
Problem
Existing receiver circuits are costly due to high-value capacitors, which increase the size and complexity of the printed circuit board, leading to potential signal disturbances and reduced sensitivity.
Innovation Solution
The proposed receiver circuit eliminates the need for a peak detector and associated high-value capacitors by using an operational transconductance amplifier to adjust the gain of the first amplifier stage, coupled with a comparator and hysteresis block to provide a stable and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-value capacitors are used in the envelope detector stage, peak detector stage, and connection track, then the circuit can detect and compare signal levels, but the cost increases, the printed circuit board surface area increases, and the risk of signal oscillation increases
Solution Approach 1:
The patent removes the peak detector stage and its associated high-value capacitor from the circuit. The envelope detector stage is modified to function without requiring a peak detector, thereby eliminating one high-value capacitor and reducing circuit complexity while maintaining the ability to detect signal levels through the modified envelope detection mechanism
Solution Approach 2:
The patent changes the operational parameters of the envelope detector stage by using an operational transconductance amplifier with adjustable gain controlled by a control voltage. This allows the envelope detector to adapt its sensitivity and operating point, enabling it to perform level detection functions previously requiring separate peak detection circuitry, thereby reducing the number of high-value capacitors needed
2Reliability
If high-value capacitors are used in the receiver circuit, then signal level detection and comparison can be performed, but the manufacturing cost increases due to expensive capacitor technologies
Solution Approach 1:
The patent eliminates the peak detector stage and its associated high-value capacitor, reducing the total number of expensive high-value capacitors from three to one (retaining only the protection capacitor in the envelope detector stage), thereby significantly reducing manufacturing costs while maintaining signal level detection capability through the modified envelope detection approach
Solution Approach 2:
The patent replaces expensive high-value capacitors with standard-value capacitors and uses an operational transconductance amplifier with voltage-controlled gain to achieve the necessary signal level detection and comparison functions. This substitution uses cheaper, more readily available components while maintaining functional equivalence through active circuitry rather than passive energy storage elements
3Reliability
If high-value capacitors are used in the receiver circuit, then envelope detection and signal comparison can be achieved, but the printed circuit board surface area increases
Solution Approach 1:
The patent removes the peak detector stage and its associated high-value capacitor, eliminating the need for additional large capacitor components and their associated PCB footprint. The modified envelope detector stage achieves signal level detection without requiring the additional space that would be needed for separate peak detection circuitry and its high-value capacitor
Solution Approach 2:
The patent combines the functions of envelope detection and signal level comparison into a single integrated stage. The operational transconductance amplifier in the envelope detector stage is used to both detect the envelope and provide voltage-controlled gain for signal level comparison, eliminating the need for separate peak detection circuitry and reducing the overall PCB area required
4Reliability
If multiple high-value capacitors are used in the receiver circuit, then signal detection and gain control can be performed, but signal oscillation disturbances increase
Solution Approach 1:
The patent removes the peak detector stage and its associated high-value capacitor, reducing the total number of high-value capacitors in the circuit. This reduction in the number of high-value capacitors directly decreases the risk of signal oscillation disturbances while maintaining signal detection accuracy through the modified envelope detection mechanism with voltage-controlled gain
Solution Approach 2:
The patent introduces a control voltage mechanism that provides feedback control of the operational transconductance amplifier gain. This feedback mechanism allows dynamic adjustment of the envelope detector gain to optimize signal detection while preventing oscillation conditions, replacing the need for multiple high-value capacitors that would otherwise be required for stable operation
Data Source
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Figure 3
AI summary
The present invention relates to a receiver system comprising an input terminal through which an input signal is received, said receiver circuit further comprising: - a first amplifier stage connected by its input to the input terminal of said receiver circuit; - an envelope detector stage consisting of detecting the maxima of the received signal so as to restore its envelope, said detector stage being connected to the output of the first stage.