The CDMS II Veto Readout Electronics
#sample and hold
#analog-digital
#pulse height
#threshold detection
#front end amps
#mixed signal
#readout electronics
#prototype
Description: A Prototype Sample and Hold Circuit - The original concept for the veto front-end amplifiers was to continuously sample the input pulse height and maintain the pulse height for any pulses exceeding a low voltage threshold (approximately 10 mV). This mixed analog and digital circuit was successfully implemented. However, the highly variable rise times of the input pulses result in significant pulse height errors for all but a very limited range of input pulse heights.
The prototype sample and hold circuit is designed to capture and retain the amplitude of input pulses that exceed a specified voltage threshold. The primary function of this circuit is to ensure that only valid pulses, which surpass the threshold of approximately 10 mV, are processed further. The circuit operates by continuously sampling the input signal using a comparator to determine when the signal exceeds the defined threshold. Upon detecting a valid pulse, the circuit engages a sample and hold mechanism that captures the peak voltage of the pulse.
The implementation of the mixed analog and digital components allows for effective integration of the sampling process with digital logic for subsequent signal processing. The analog section typically includes operational amplifiers configured as comparators and sample-and-hold circuits, while the digital section may consist of a microcontroller or digital signal processor to handle the logic and control functions.
Challenges arise due to the variable rise times of the input pulses, which can lead to inaccuracies in the captured pulse heights. This variability can introduce significant errors, particularly for input pulses that fall outside the optimal range. To mitigate these issues, careful design considerations must be made, including the selection of appropriate components that can handle the dynamic characteristics of the input signals. Additionally, implementing filtering techniques and optimizing the timing of the sample and hold circuit can enhance performance and accuracy.
Overall, this prototype serves as a foundational circuit for applications requiring precise pulse height measurements while highlighting the importance of addressing rise time variability to improve reliability across a broader range of input conditions.A Prototype Sample and Hold Circuit -The original idea for the veto front end amps was to continually sample the input pulse height and hold the pulse height for any pulses passing a low voltage threshold (~10mV). This mixed analog and digital circuit was actually made to work. Unfortunately, the highly variable risetimes of the input pulses cause d large pulse height errors for all but a very limitied range of input pulse heights.
The prototype sample and hold circuit is designed to capture and retain the amplitude of input pulses that exceed a specified voltage threshold. The primary function of this circuit is to ensure that only valid pulses, which surpass the threshold of approximately 10 mV, are processed further. The circuit operates by continuously sampling the input signal using a comparator to determine when the signal exceeds the defined threshold. Upon detecting a valid pulse, the circuit engages a sample and hold mechanism that captures the peak voltage of the pulse.
The implementation of the mixed analog and digital components allows for effective integration of the sampling process with digital logic for subsequent signal processing. The analog section typically includes operational amplifiers configured as comparators and sample-and-hold circuits, while the digital section may consist of a microcontroller or digital signal processor to handle the logic and control functions.
Challenges arise due to the variable rise times of the input pulses, which can lead to inaccuracies in the captured pulse heights. This variability can introduce significant errors, particularly for input pulses that fall outside the optimal range. To mitigate these issues, careful design considerations must be made, including the selection of appropriate components that can handle the dynamic characteristics of the input signals. Additionally, implementing filtering techniques and optimizing the timing of the sample and hold circuit can enhance performance and accuracy.
Overall, this prototype serves as a foundational circuit for applications requiring precise pulse height measurements while highlighting the importance of addressing rise time variability to improve reliability across a broader range of input conditions.A Prototype Sample and Hold Circuit -The original idea for the veto front end amps was to continually sample the input pulse height and hold the pulse height for any pulses passing a low voltage threshold (~10mV). This mixed analog and digital circuit was actually made to work. Unfortunately, the highly variable risetimes of the input pulses cause d large pulse height errors for all but a very limitied range of input pulse heights.
High speed sample and hold
This circuit demonstrates a 10 V acquisition time of 900 ns with 0% accuracy and a droop rate of only 100 µV/ms at an ambient temperature of 25°C. A faster acquisition time can be achieved by using a smaller hold-capacitor...
Sample and hold
The 2N4393 JFET was chosen due to its low gate leakage current (less than 100 pA), very low drain current (ID less than 100 pA), and low pinch-off voltage. Leakage levels of this magnitude impose strict requirements on circuit performance,...
Sample and hold
The JFETs, Q1 and Q2, provide complete buffering to C1, the sample and hold capacitor. During the sample phase, Q1 is activated, establishing a low-resistance path (rds(on)) for charging C1. In the hold phase, Q1 is deactivated, leaving Q1 Id...
Flunn paralell path
An RPM test was uploaded, conducted a few months ago with the initial prototype of the PPMM, designated SRSM1. The video can be found on the YouTube channel of scienculo.
The RPM test involves measuring the rotational speed of a motor...
Performance sample and hold
When switch SW1 is in the positive position, the FET is activated, exhibiting a resistance of approximately 400 ohms. The input voltage charges the capacitor through the FET. Conversely, when SW1 is in the negative position, the FET is deactivated...
Infinite sample and hold amplifier
During normal hold mode, the replicated analog voltage is buffered directly through the sample-and-hold (S/H) amplifier to the output. Upon receiving a SAMPLE signal, the S/H amplifier enters hold mode, maintaining the voltage until the new analog voltage is valid....
Sample and hold circuit II
This circuit quickly charges capacitor CST0 to a voltage that matches an input signal. After charging, the input signal is electrically disconnected from the capacitor, allowing the charge to remain on CST0. Since CST0 is part of the negative feedback...
Peak voltage sample and hold circuit
The peak voltage sample and hold circuit is illustrated in Figure 12-50. This circuit comprises the LF398 sample and hold chip and the LM311 voltage comparator. The LF398 is responsible for outputting and inputting voltages. The LM311 compares the input...
MFOS Micro-Sample & Hold circuit
The voltage to be sampled is applied to the input of R2, a 100K linear taper potentiometer, while the other end of R2 is grounded. Consequently, the signal level that is sent to the buffering level shifter U1-A and its...