SYSTEM AND METHOD OF ALTERING A PWM CARRIER POWER SPECTRUM
First Claim
1. A system comprising:
- a first superframe structure including a first-superframe input configured to receive a first pulse width modulated (PWM) signal and including a first-superframe output, the first superframe structure configured to selectively apply a modulation operation to the first PWM signal according to a pre-determined superframe pattern to produce a superframed signal at the first-superframe output;
a second superframe structure including a second-superframe input configured to receive a second PWM signal that is a duty cycle complement of the first PWM signal and including a second-superframe output, the second superframe structure configured to selectively apply the modulation operation to the second PWM signal according to a complement of the pre-determined superframe pattern to produce a complementary-superframed signal at the second-superframe output;
a switch including a first input coupled to the first-superframe output, a second input coupled to the second-superframe output, a control input, and a switch output, the switch configured to receive a control signal at the control input and to selectively provide one of the superframed signal and the complementary-superframed signal to the switch output as a modulated output signal; and
wherein the modulation operation comprises one of a phase shift operation and a chop operation.
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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
20 Claims
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1. A system comprising:
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a first superframe structure including a first-superframe input configured to receive a first pulse width modulated (PWM) signal and including a first-superframe output, the first superframe structure configured to selectively apply a modulation operation to the first PWM signal according to a pre-determined superframe pattern to produce a superframed signal at the first-superframe output; a second superframe structure including a second-superframe input configured to receive a second PWM signal that is a duty cycle complement of the first PWM signal and including a second-superframe output, the second superframe structure configured to selectively apply the modulation operation to the second PWM signal according to a complement of the pre-determined superframe pattern to produce a complementary-superframed signal at the second-superframe output; a switch including a first input coupled to the first-superframe output, a second input coupled to the second-superframe output, a control input, and a switch output, the switch configured to receive a control signal at the control input and to selectively provide one of the superframed signal and the complementary-superframed signal to the switch output as a modulated output signal; and wherein the modulation operation comprises one of a phase shift operation and a chop operation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A circuit comprising:
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a plurality of superframe structures, each of the plurality of superframe structures including an input to receive a pulse width modulated (PWM) signal and including an output, each of the plurality of superframe structures configured to selectively apply a modulation operation to the PWM signal according to one of a plurality of superframe patterns to produce a superframed PWM signal; a switch including a plurality of inputs coupled to the outputs of the plurality of superframe structures, a control input, and a switch output; and a control circuit coupled to the control input and configured to control the switch to selectively provide the superframed PWM signal of one of the outputs of the plurality of superframe structures to the switch output as a modulated PWM signal. - View Dependent Claims (13, 14, 15, 16)
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17. A system comprising:
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a pulse edge controller comprising; a first input for receiving a pulse width modulated (PWM) signal; a second input for receiving a duty cycle complement of the PWM signal; a control input; a first output; a second output; and logic circuitry coupled to the control input and configurable to selectively apply a modulation operation to the PWM signal and the duty cycle complement of the PWM signal to produce modulated PWM output signals at the first and second outputs in response to a superframe pattern received at the control input; and a control circuit coupled to the control input and adapted to apply the superframe pattern selectively to the control input to control operation of the logic circuitry. - View Dependent Claims (18, 19, 20)
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Specification