Track & Hold (T&H) is a function or module that samples and holds a control voltage (CV) or audio signal at a specific value when it receives a trigger or gate signal. The held value remains constant until the next trigger or gate signal is received, at which point the module samples the input signal again and holds the new value.
The Track & Hold function is similar to the Sample & Hold (S&H) function, but with a slight difference in behavior. In a Sample & Hold module, the input signal is only sampled and held when a trigger or gate signal is received. In contrast, a Track & Hold module continuously “tracks” or follows the input signal while the gate signal is high (or active) and then holds the last value when the gate signal goes low (or inactive).
Track & Hold can be used for a variety of purposes in modular synthesis, such as:
- Creating stepped modulation patterns by sampling an LFO or random voltage source at specific intervals.
- Freezing the pitch of an oscillator when a gate signal is received, allowing for pitch changes only when the gate is inactive.
- Capturing the value of a continuously changing CV signal at specific moments for further processing or modulation purposes.