DIGITAL PULSE-WIDTH MODULATOR HAVING DISTRIBUTED SPECTRAL CHARACTERISTIC Russian patent published in 2007 - IPC H03K7/08 

FIELD: digital automatic-control systems for electric drives of microprocessor systems for pulsed regulation of motor supply voltage.

SUBSTANCE: pulse-width modulator period varies obeying random law affording uniform distribution within desired range. Proposed pulse-width modulator has sync pulse generator 1 and comparator 8. Newly introduced are pseudorandom number generator 2, change-over units 3, 6, memory registers 4, 7, adder 5, and limiting unit 3. Output of pseudorandom number generator 2 is connected to first input of change-over unit 3. Output of the latter is connected to input of memory register 4. Output of memory register 4 is also connected to first input of adder 5 and to second input of change-over unit 3. Output of adder 5 is connected to first input of change-over unit 6. Output of the latter is connected to second memory register 7 whose output is also connected to third input of change-over unit 3, to second input of adder 5, to second input of change-over unit 6, and to first input of comparator 8. Output of comparator 8 functions as that of pulse-width modulator. Output of limiting unit 9 whose input functions as pulse-width modulator input is connected to second input of comparator 8.

EFFECT: ability of distributing electric-drive vibration-noise characteristic spectrum due to expanding pulse-width modulator spectral characteristic.

1 cl, 2 dwg