Signal Chain Reconfiguration for Capacitive and Piezoresistive Transducer Alternates
Reconfiguring signal chains between capacitive and piezoresistive transducers requires matching input impedance, excitation sources, and thermal compensation math.
Switched Capacitor Circuits
Discrete Integration
Discrete-time analog signal processing architectures replace high-value integrated resistors with capacitors periodically connected via solid-state switches. Modern switched capacitor circuits emulate resistive elements through controlled charge transfer driven by high-frequency non-overlapping clock signals. Signal processing limits occur where switching speeds approach amplifier bandwidth limits or charge injection dominates baseline precision.
Charge Transfer
Opening and closing switch pairs transfers discrete charge packets between sampling and integrating capacitors during each clock phase. Equivalent resistance equals the reciprocal of clock frequency multiplied by sampling capacitance value. Monolithic silicon processes achieve high relative capacitor matching accuracy, enabling precise filter cutoffs and gain ratios without laser trimming.
Frequency Scaling
Filter corner frequencies and amplifier gain ratios scale directly with master clock frequency, allowing dynamic tuning across wide operational bandwidths. Low temperature coefficients of silicon dioxide capacitors yield superior thermal stability compared to integrated diffusion resistors. Clock feedthrough and switch gate charge injection introduce discrete voltage offsets into signal paths.
Clock jitter creates phase noise that elevates baseline conversion noise floors during high-speed sampling operations. Parasitic capacitance at internal switch nodes alters charge transfer ratios if uncompensated by circuit layout.
Metrological Characterization
Precision signal generators deliver low-distortion sine waves to evaluate frequency response and harmonic distortion. Automated test systems verify clock frequency scaling accuracy and clock feedthrough suppression across operational ranges. Test reports record total harmonic distortion and signal-to-noise metrics under standardized clock driving conditions.