Coefficients/Potentiometers

Coefficients are quantitative parameters that enter analog computations in a multiplicative fashion. The Analog Thing features eight coefficient potentiometers, allowing the use of up to eight coefficients in an analog computation. Using the potentiometers, each coefficient can be set to any value between 0 and +1. An input to a coefficient potentiometer is multiplied by the value the coefficient potentiometer is set to such that their output is given by output = coefficient * input.

Five sections of the THAT user interface relate to the use of coefficient potentiometers, as shown in Figure 1:

• the COEFF section: these are inputs and output sockets
• the COEFFICIENT POTENTIOMETERS section
• the MODE selector
• the COEFFICIENT selector
• the digital voltmeter

To familiarize yourself with the use of coefficient potentiometers, follow these steps:

1. Set the MODE selector to position COEFF and set the COEFFICIENT selector to position 1. This connects the output of potentiometer COEFF 1 to the digital voltmeter.
2. Use a patch cable to connect one of the +1 jacks in the STABILIZED ±1 section to the input (circle) associated with potentiometer COEFF 1 in the COEFFICIENTS section (i.e., the uppermost circled jack in the section labelled COEFF on your THAT).
3. Change the position of the COEFF 1 knob in the COEFFICIENT POTENTIOMETERS section and observe the value displayed on the digital voltmeter. The displayed value is available at the output (triangle) associated with potentiometer COEFF 1 in the COEFFICIENT section.
4. Remove the patch cable plug from the +1 jack in the STABILIZED ±1 section and plug it into one of the -1 jacks in in the STABILIZED ±1.
5. Again, change the position of the COEFF 1 knob in the potentiometer section and observe the value displayed on the digital voltmeter.
6. Set the COEFFICIENT selector to any one of the other potentiometers (say, 4).
7. Use a patch cable to connect either of the -1 jacks in the STABILIZED ±1 with the input (circle) associated with the with the coefficient potentiometer you have chosen using the COEFFICIENT selector (say, 4).
8. Change the position of the coefficient potentiometer knob associated with the coefficient you have chosen using the COEFFICIENT selector (say, 4) and again observe the value displayed on the digital voltmeter.

Figure 1: Parts of the THAT user interface that relate to the familiarization steps described above