摘要:
Clock and data recovery (CDR) circuits and resettable voltage controlled oscillators (VCOs) are disclosed. In one embodiment, the CDR circuit includes a sampler configured to receive a data stream in a data path and sample the data stream. However, a clock signal of the data stream needs to be recovered to sample the data stream since the data stream may not be accompanied by the clock signal. To recover the clock signal from the data stream, the CDR circuit may have a resettable VCO configured to generate a clock output. The sampler and the resettable VCO may be operably associated so that the sampler samples the data stream in the data path based on the clock output. The resettable VCO can be reset to adjust a clock phase of the clock output and help reduce sampling errors resulting from drift of the clock output and/or the data stream.
摘要:
A pulse width modulated (PWM) signal is received and, over a time interval of the PWM signal, a first count is incremented when the PWM signal is at a first level, and a second count is incremented when the PWM signal is at a second level. At the end of time interval the first count is compared to the second count and, based on the comparison, a decoded bit is generated. Optionally, incrementing the first count is by enabling a first oscillator that increments a first counter, and incrementing the second count is by enabling a second oscillator that increments a second counter.
摘要:
An amplitude control circuit includes a pair of peak detectors. The pair of peak detectors are responsive to a voltage reference generator. The amplitude control circuit is configured to be responsive to an oscillating signal of a crystal oscillator and configured to generate a control signal to control an amplitude of the oscillating signal.
摘要:
A pulse width modulated (PWM) signal is received and, over a time interval of the PWM signal, a first count is incremented when the PWM signal is at a first level, and a second count is incremented when the PWM signal is at a second level. At the end of time interval the first count is compared to the second count and, based on the comparison, a decoded bit is generated. Optionally, incrementing the first count is by enabling a first oscillator that increments a first counter, and incrementing the second count is by enabling a second oscillator that increments a second counter.
摘要:
A method of tuning channels for television and community antenna television (CATV) devices includes the step of receiving a radio frequency input (RFI) signal having at least one carrier signal at frequency f.sub.s associated with a selected broadcast channel. The RFI signal is up-converted by m to a first intermediate frequency wherein the carrier signal is located at f.sub.s +m. The first intermediate frequency is filtered. The filtered first intermediate frequency is down-converted by n to a second intermediate frequency wherein the second intermediate frequency includes the carrier signal at f.sub.s +m-n. Additional methods for improving the reception of the selected channel include the step of varying m and n in order to avoid frequency-dependent anomalies within the pass band of the filter. For digital communications, m and n are varied in accordance with an error rate of the digital communications in order to reduce the error rate of the digital communications.
摘要:
An amplitude control circuit includes a pair of peak detectors. The pair of peak detectors are responsive to a voltage reference generator. The amplitude control circuit is configured to be responsive to an oscillating signal of a crystal oscillator and configured to generate a control signal to control an amplitude of the oscillating signal.