CV Processor

Scaling Processor (SPRC)
The SCALING PROCESSOR (SPRC) is similar to the Dual Processor except it has three sections. The top two sections have one fixed gain input and one input with full processing. The bottom section has two inputs with full processing control (scaling and inverting) as well as an offset control. A fixed +5 volts is available at all times for use as an offset bias for the above sections or to change the range of a module or set or modules.

Dual Processor (PRC)
The DUAL PROCESSOR (PRC) is two independent circuits for adding and inverting control voltages. Full processing control of level and polarity of three inputs voltages Is provided. A manual offset voltage can be set to be added to the other three inputs.

Active Processor (ACPR)
The ACTIVE PROCESSOR (ACPR) is an accurate, linear cross-fader for either control voltages or audio signals. This module provides an important link in complex patches, allowing the user to smoothly change from one control voltage to another. It is possible to cross-fade between different envelopes, for example, or to gradually switch control over a bank of oscillators from one output of a sequencer to another output. A scaling buffer is included in the bottom section to further invert and process control voltages.

Dual Comparator (COM)
The DUAL COMPARATOR (COM) provides several often useful house-keeping functions within the Serge system:

• Logical Decisions: If the + input is greater than the - input, then the output will be high. If not, then the output will be low. 
• Level Detection. A pulse will be generated whenever an input voltage reaches a pre-set threshold. For example, when an envelope detector reaches a certain loudness level, it can be used with the Comparator to generate a pulse to activate or de-activate other events programmed within the synthesizer. 
• Voltage variable pulse width modulation of any of the Serge oscillators. 
• “Squaring” audio signals, whereby frequency related pulses are derived from an input signal. These pulses can be used for frequency sub-division (via a Dual Slope Generator or Sequencer), or as raw audio, rich in harmonic content. 

In addition to the +/- inputs, each of the Comparators include a front-panel knob to manually set a threshold.

Dual Schmitt Triggers (STR)
The DUAL SCHMITT TRIGGER (STR) is similar to the Dual Comparator, except that it has been optimized for squaring up audio signals. The Schmitt Trigger is a single-input comparator with hysteresis. Hysteresis means that the switching thresholds are different for an input signal depending upon whether it is going up or down. This feature can be used with an envelope and VCA functioning as a noise gate to reject low-level background noise in audio applications. The Schmitt Triggers can be used for level detection, plus they have a function unique to the module: both sections of the module can be used as a “set-reset flip-flop”. Essentially, this is a memory element. A pulse or level into the SET input sets the R/S output high. This output will stay high independently of the activity at the SET input. It is reset to zero when the RESET input receives a pulse of sufficient level.