Schematics / Sample And Hold By Carsten Toensmann
Sample and Hold by Carsten Toensmann ,visit Analog Monster page for more details on this module http://www.analog-monster.de/suh_en.html ,from there the brief technical description :
The module is built around an LF398 Sample and Hold chip. The rising edge of the clock- / trigger signal (0V => 5V) triggers a 4098 monoflop which sends a 10µs 5V pulse to the sample control input of the LF398 which stores the input signal voltage in a hold capacitor during this time. After termination of the sample pulse the signal voltage value is kept by the capacitor. The output of the LF398 is given to a pair of opamps for each signal path. On one signal path the first opamp works as an inverting amplifier, on the other signal path it is a non inverting one. According to the 'Glide' switch position the output voltage passes a portamento circuit (pot plus capacity) or is connected directly to the output buffer stage (2nd opamp of the signal path). As I wanted to display the current glide selection optically I used a double switch for glide activation. The other swich is used to switch on the control LED. To let the 4098 start in a defined behaviour I implemented a chip reset of one second (1m resistor and 1µ capacity).