SYSTEM AND METHOD OF ALTERING A PWM CARRIER POWER SPECTRUM
First Claim
1. A circuit device to produce an output signal with suppressed common mode carrier power, the circuit device comprising:
- differential inputs to receive differential pulse-width modulated (PWM) signals; and
a pulse edge control circuit coupled to the differential inputs and configured to phase-shift or chop the differential PWM signals according to a control signal to generate a modulated PWM output signal with suppressed common mode carrier power.
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Abstract
In a particular embodiment, a circuit device includes an input to receive a pulse-width modulated (PWM) signal and an output to send a modulated PWM signal. The circuit device further includes a pulse edge control circuit coupled between the input and the output. The pulse edge control circuit receives the PWM signal via the input and includes a control input to receive a modulation control signal. The pulse edge control circuit is adapted to modify the PWM signal to provide the modulated PWM signal with suppressed carrier power and associated harmonics to the output based on the modulation control signal. The circuit device further includes a modulation sequence controller adapted to provide the modulation control signal via the control input. The modulation control signal selectively controls a sequence of the modification of the PWM signal to selectively alter an output power spectrum of the modulated PWM signal.
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Citations
35 Claims
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1. A circuit device to produce an output signal with suppressed common mode carrier power, the circuit device comprising:
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differential inputs to receive differential pulse-width modulated (PWM) signals; and a pulse edge control circuit coupled to the differential inputs and configured to phase-shift or chop the differential PWM signals according to a control signal to generate a modulated PWM output signal with suppressed common mode carrier power. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of altering a power spectrum of a signal, the method comprising the acts of:
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receiving a pulse-width modulated (PWM) signal at a pulse edge controller of a circuit device; receiving a control signal defining a pattern at the pulse edge controller; and in response to receiving the control signal, selectively modifying the received PWM signal according to the pattern to produce a modulated PWM output signal having an altered power spectrum relative to a power spectrum of the received PWM signal. - View Dependent Claims (11, 12, 13, 14, 15)
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16. An apparatus to produce a modulated PWM signal, the apparatus comprising:
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a control circuit configured to generate a control signal including a pattern of symbols; and a pulse edge control circuit configured to receive a PWM signal and, in response to the control signal, to perform a sequence of phase-shift operations or chopping operations on the PWM signal to produce a modulated PWM signal, the sequence corresponding to the pattern of symbols. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method of altering a power spectrum of a signal, the method comprising the acts of:
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receiving a pulse-width modulated (PWM) signal; modifying the PWM signal to produce a modulated PWM signal with suppressed carrier power and associated harmonics; and selectively controlling a modification sequence associated with producing the modulated PWM signal to selectively alter a PWM carrier power spectrum to produce a modulated PWM output signal having at least one of a reduced peak carrier power and frequency notches at particular frequencies. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A circuit device comprising:
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a differential switching amplifier including at least one positive input and at least one negative input and a differential output coupled to a load; a pulse edge control circuit coupled to the at least one positive input and the at least one negative input of the switching amplifier to receive differential PWM signals and including a modulation control input to receive a modulation control signal, the pulse edge control circuit adapted to phase-shift or chop the differential PWM signals to produce a modulated PWM output signal with suppressed common mode carrier power and associated harmonics; and a modulation sequence controller coupled to the modulation control input to selectively control a sequencing of the phase-shifting or chopping operation to selectively alter a common mode power spectrum of the modulated PWM output signal. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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Specification