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Revision 15 as of 2017-07-04 04:24:33

location: SineCore

SineCore Modulator

About the SineCore Modulator

The SineCore Modulator is based on a design by Barrie Gilbert from 1977. It uses a series of cascaded differential amplifiers to smoothly change the polarity of the output signal as the input voltage is increased. This became the basis for the AD639 "Universal Trigonemtric Function Converter" IC from Analog Devices, Inc. The SineCore Modulator can produce +/-720 degrees of a relatively low distortion sinewave. Over the first +/-90 degrees, the THD is around -80dB, making it very useful for triangle or sawtooth to sinewave conversion. If the amplitude of the input signal is modulated, the number of reversals increases, essentially acting as a quadruple wavefolder. When a sawtooth wave is applied, it can be summed with a DC offset to produce sinewave Phase Modulation (PM) with through-zero capability.

How to Use the SineCore Modulator

The module comes in a 14P Wide-DIP format. The pins are labeled 1 to 7 from top to bottom on 2 headers, J1 and J2. Don't ask me why its that way as compared to the conventional labeling of 1 to 14, as there is no good reason. The pins are as follows:





Positive input - base of modulator transistor


Shield - connect to ground if used


Shield - connect to ground if used


Alternate current control - emitters of modulator transistors


Negative input - base of modulator transistor


Negative outout - collectors of modulator transistors


Positive output - collectors of modulator transistors

Over-voltage Protection