The A148 has two identical sample & hold modules, designed to produce “staircase” voltages. The signal present at the sample input is sampled at a rate set by the trigger input, and held at that voltage at the S&H output. The exact shape of the staircase depends on the sort of waveform at the sample input: NOISE or RANDOM signals produce random patterns, an LFO produces rising and falling staircase patterns. Two LED’s for each S&H indicate the voltage (positive or negative) of the sampled signal.
Each half fo the A-148 can operate as a S&H (sample&hold) or T&H (track&hold), this can be selected by a jumper. In T&H mode the output signal follows the input signal while the trigger input is "high". As soon as the trigger input turns to "low" the last voltage is stored. The factory setting is S&H for the upper part and T&H for the lower part. In addition the complete A-100 voltage range -12...+12V can be processed.