Phase-Modulation Converter Calibration for PCB Delay Compensation
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Solution Overview
Problem
Conventional analog-to-digital converters face challenges in calibration due to PCB time delays and bidirectional input requirements, leading to circuit complexity and inaccuracy, particularly in phase-modulation converters.
Innovation Solution
A method and phase-modulation converter with a calibration switch and dynamic phase position adjustment of the reference signal, allowing for calibration without influencing the system, using a calibration switch to connect the adder to earth or ground, and adjusting the phase position to achieve a calibrated output value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed using conventional methods with SSR relays or transistors, then offset compensation is achieved, but circuit complexity increases and sensor short-circuit risk arises
Solution Approach 1:
The calibration function is extracted from the main signal path by using a calibration switch that connects the adder input to ground only during calibration mode. This separates the calibration operation from normal measurement operation, eliminating the need for complex relay or transistor-based calibration circuits while preventing sensor short-circuit during calibration.
Solution Approach 2:
A calibration switch is introduced as an intermediary component that safely connects the adder input to ground during calibration. This mediator enables offset compensation without directly short-circuiting the sensor, as the switch isolates the sensor from the ground connection during calibration mode.
2Adaptability or versatility
If bidirectional analog inputs are implemented, then measurement range is extended, but circuit complexity significantly increases
Solution Approach 1:
The patent replaces complex bidirectional analog circuitry with a phase-modulation converter that uses digital signal processing. The analog input is converted to digital values through phase modulation and correlation, eliminating the need for complex bidirectional analog amplification stages, multiple supply voltages, and precision resistance networks.
Solution Approach 2:
The patent changes the measurement parameter from direct analog voltage level detection to phase difference measurement. By measuring the phase difference between the input signal and a reference signal, the system can determine both magnitude and polarity of analog inputs using simpler circuitry, as the phase information encodes the bidirectional measurement data.
3Manufacturing precision
If PCB time delays are not compensated, then circuit simplicity is maintained, but measurement accuracy deteriorates
Solution Approach 1:
The patent performs preliminary calibration to compensate for PCB time delays by adjusting the phase of the reference signal. This preliminary adjustment is stored and applied during normal operation, eliminating the need for complex real-time delay compensation circuits while maintaining measurement accuracy.
Solution Approach 2:
The patent uses feedback from the correlation output to adjust the reference signal phase. During calibration, the system measures the actual phase delay introduced by PCB traces and uses this feedback information to pre-adjust the reference signal phase, compensating for the fixed time delays in the signal path.
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
Enables reliable calibration of phase-modulation converters with minimal circuit complexity, compensating for production and construction tolerances, and maintaining a constant signal-to-noise ratio across input voltages.
Implementation Method 1
an amplitude modulator with carrier suppression to which an input signal to be converted can be supplied on an input side to obtain a carrier-free amplitude-modulated signal
Implementation Method 2
an adder to add a phase-displaced, preferably sinusoidal, adder carrier signal to the carrier-free amplitude-modulated signal and to obtain a phase-modulated signal
Implementation Method 3
a limiter to which the phase-modulated signal output by the adder is supplied and which is configured to suppress an interference-induced amplitude modulation in the phase-modulated signal
Implementation Method 4
a demodulation facility to which the signal output by the limiter can be supplied and demodulated therein, wherein, in the context of the demodulation, a comparison of the signal output by the limiter with a reference signal can occur
Data Source
AI summary
A method for calibrating a phase-modulation converter that includes an amplitude modulator with carrier suppression, an adder, a limiter and a demodulation facility to which a signal output by the limiter is suppliable and demodulated therein, wherein a comparison of the signal output by the limiter with a reference signal occurs in the context of the demodulation, a calibration switch, which is connected upstream of the adder which is actuatable between a control setting in which the adder, is connected via the calibration switch to the input of the phase-modulation converter, and at least one calibration setting in which the is interrupted, where in a calibration setting of the calibration switch, the phase position of the reference signal is changed, preferably dynamically, and a phase position of the reference signal is found at which an output signal of the demodulation facility assumes a calibrated value.