Applied Micro Circuits Corporation

Shyang Kye Kong

Bruce H Coy

Hongming An

Simon Pang

Philip Michael Clovis

Kenneth Smetana

Brian Lee Abernathy

Paul Edward Vanderbilt

A system and method are provided for detecting the frequency acquisition of a synthesized signal in a non-synchronous communications receiver. The method accepts a non-synchronous communication signal having an input data signaling frequency, and compares the input data signaling frequency to a synthesized signal frequency. In response to the comparing, a difference signal pulse is generated. More explicitly, the difference signal is generated at a rate responsive to the difference between the input data signaling frequency and the synthesized signal frequency. The method counts synthesized signal pulses occurring simultaneously with the difference signal pulse. If the counted synthesized signal pulses exceed a threshold (before the disappearance of the difference signal pulse), it is determined that the input data signaling frequency is about equal to the synthesized signal frequency, and a lock signal is generated.

Frequency lock detection

A system and method are provided for adjusting the phase output of a Hogge phase detector. The method comprises: using a Hogge phase detector, generating a reference signal; using the Hogge phase detector, generating a phase and reference signals; accepting an adjust signal; modifying the amplitude of the phase signal in response to the adjust signal; integrating the amplitude modified phase signal; using the integrated signal as a phase adjusted signal; integrating the reference signal; using the integrated reference signal and phase adjusted signal to generate a voltage controlled oscillator (VCO) signal; at the Hogge phase detector, accepting the VCO signal as the clock signal. Some aspects of the method further comprise: using the VCO signal to sample data at a settled first phase of the clock; changing the adjust signal; and, using the VCO signal to sample data at a settled second phase of the clock.

Hogge phase detector with adjustable phase output

A system and method are provided for measuring amplifier gain in a digital network. The method includes accepting a digital input signal; amplifying the input signal (Vin); comparing the amplified signal to dc thresholds; measuring output errors; and, calculating the amplifier gain in response to the thresholds. More specifically, accepting a digital input signal includes accepting an input signal having an amplitude. Comparing the amplified signal to dc thresholds includes comparing the amplified signal to a low threshold and a high threshold. Measuring errors includes measuring a predetermined error condition in response to the high threshold and the low threshold. Then, calculating the amplifier gain in response to the thresholds includes calculating the amplifier gain in response to the high threshold, the low threshold, and the input signal amplitude.

System and method for measuring amplifier gain in a digital network

A system and method are provided for compensating a comparator threshold level. The method comprises: accepting an input signal with an ac component; lowpass filtering the input signal to generate the input signal average voltage; accepting the input signal average voltage; accepting a first dc level; summing the average voltage with the first dc level; supplying a first sum as a first comparator threshold level; comparing the input signal to the first comparator threshold level; and, supplying a first comparator output signal with an ac component. In some aspects of the method, accepting a first dc level includes accepting a plurality of dc levels. Then, the average voltage is summed with each of the plurality of dc levels and supplied as a corresponding plurality of comparator threshold levels. The input signal is compared to each of the comparator threshold levels and a plurality of comparator output signals are supplied.

System and method for comparator threshold adjustment

A system and method are provided for controlling the phase of a voltage controlled oscillator output. The method comprises: accepting a plurality of VCO outputs coarsely differentiated by phase; selecting one of the VCO outputs; finely modifying the phase of the selected VCO output; and, supplying the phase modified VCO output. In one aspect, accepting VCO outputs coarsely differentiated by phase includes: accepting a first VCO output (I ); accepting a second VCO output (I ), differentiated approximately 90 degrees from the first VCO output; accepting a third VCO output (Q ), differentiated approximately 90 degrees from the second VCO output; and, accepting a fourth VCO output (Q ), differentiated approximately 90 degrees from the third VCO output. Finely modifying the phase of the selected VCO output includes modifying the selected VCO output in the range between &plus;45 and &minus;45 degrees. In one aspect, the output is modified in 16 discrete steps.

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San Diego, CA, United States of America

Shyang Kye Kong