Frequency Transposition Circuit With Output Voltage Reset
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Solution Overview
Problem
Frequency transposition of analog signals often leads to gain degradation due to stray capacitances in amplifier stages, causing partial discharge of output capacitors during the process.
Innovation Solution
A method and device that involve delivering the incident signal to a transconductor stage, where the current output is connected to an output capacitor for at least part of each half-period of a periodic signal, and resetting the voltage of the current output to match the voltage of the output capacitor, thereby preventing voltage differences and stray currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency transposition is carried out by inverting the sign of the incident analog signal at the rhythm of a periodic signal to control a set of switches, then frequency transposition is achieved, but gain degradation occurs due to stray capacitances causing partial discharge of the output capacitor
Solution Approach 1:
The patent applies preliminary action by resetting the voltage of the current output to match the voltage of the output capacitor before each switching operation. This preparatory voltage equalization prevents stray currents from flowing when the switch connects the transconductor stage to the output capacitor, thereby eliminating the harmful discharge effect while maintaining the frequency transposition function
Solution Approach 2:
The patent implements equipotentiality by ensuring that the current output and output capacitor are at the same voltage potential before switching occurs. The reset mechanism equalizes the voltages, creating an equipotential state that eliminates voltage difference-driven stray currents. This maintains energy conservation during the switching operation while achieving frequency transposition
2Productivity
If the current output is connected to the output capacitor during half-periods of the periodic signal, then frequency transposition is achieved, but stray currents flow due to voltage differences, degrading the gain
Solution Approach 1:
Before connecting the current output to the output capacitor during each half-period, the patent performs a preliminary reset operation that equalizes their voltages. This preliminary action eliminates the voltage difference that would otherwise drive harmful stray currents, allowing the switching operation to proceed without energy loss while maintaining frequency transposition productivity
Solution Approach 2:
The patent converts the potentially harmful voltage difference into a beneficial control mechanism. By intentionally resetting the voltage to match before switching, the system transforms what would be a harmful stray current condition into a controlled, predictable operation where the voltage equalization itself becomes the protective mechanism that enables clean switching and maintains gain stability
Data Source
AI summary
A method is for processing an incident signal, in which the incident signal is delivered to a transconductor stage, and a current output of the transconductor stage is coupled to an output capacitor so as to deliver to the output capacitor a current signal lasting for at least part of the first half-period of each period of a periodic signal and to thus obtain a frequency-transposed signal at the output capacitor. Upon the occurrence of each part of the first half-period, the voltage of the current output, seen from the output capacitor, is reset to a value equal to that of the voltage of the output capacitor.