Abstract: A system and method are provided for resynchronizing a transmission signal using a jitter-attenuated clock derived from an asynchronous gapped clock. A first-in first-out (FIFO) memory accepts an asynchronous gapped clock derived from a first clock having a first frequency. The gapped clock has an average second frequency less than the first frequency. The input serial stream of data is loaded at a rate responsive to the gapped clock. A dynamic numerator (DN) and dynamic denominator (DD) are iteratively calculated for the gapped clock, averaged, and an averaged numerator (A and an averaged denominator (AD) are generated. The first frequency is multiplied by the ratio of AN/AD to create a jitter-attenuated second clock having the second frequency. The FIFO memory accepts the jitter-attenuated second clock and supplies data from memory at the second frequency. A framer accepts the data from the FIFO memory and the jitter-attenuated second clock.

Abstract: A method is provided for synthesizing signal frequencies using low resolution rational division. A reference frequency value and synthesized frequency value are accepted. In response to dividing the synthesized frequency value by the reference frequency value, an integer value numerator (n) and an integer value denominator (d) are determined, with n/d=I(N/D)=I+N/D=(I+1)?(D?N)/D), and where N/D<1. An accumulator creates a sum of (D?N) and a count from a previous cycle, and creates a difference between the sum and the denominator. The sum is compared with the denominator, and a first carry bit is generated. The complement of the first carry bit is added to a first binary sequence, and the first binary sequence is used to generate a k-bit quotient. The k-bit quotient is subtracted from (I+1) to generate a divisor.

Abstract: A system and method are provided for generating a jitter-attenuated clock using an asynchronous gapped clock source. The method accepts a first reference clock having a first frequency. Using the first reference clock, an asynchronous gapped clock is generated having an average second frequency less than the first frequency. A dynamic numerator (DN) and dynamic denominator (DD) are iteratively calculated for the gapped clock. Then, DN and DD are averaged. In response to the averaging, an averaged numerator (AN) and an averaged denominator (AD) are generated. Finally, the first frequency (first reference clock) is multiplied by the ratio of AN/AD to create a jitter-attenuated second clock having the second frequency.

Abstract: A method is provided for synthesizing signal frequencies using low resolution rational division decomposition in a frequency synthesis device. An integer numerator (n) and an integer denominator (d) ratio is reduced; n/d=IO(NO/DO)=IO+NO/DO=(IO+1)?(DO?NO)/DO, and where NO/DO<1 and NO and DO are integers. NO is reduced; NO=In(Nn/Dn)=In+Nn/Dn=(In+1)?(Dn?Nn)/Dn, where In, Nn, and Dn are integers, and Nn/Dn<1. In, Nn, and Dn are used to create a final numerator divisor. DO is reduced; DO=Id(Nd/Dd)=Id+Nd/Dd=(Id+1)?(Dd?Nd)/Dd, where Id, Nd, and Dd are integers, and Nd/Dd<1. Id, Nd, and Dd are used to create a final denominator divisor. Finally, IO, the final numerator divisor, and the final denominator divisor are used to create a final divisor.

Abstract: Adaptive multi-band frequency calibration is provided for a phase-locked loop (PLL). A voltage controller oscillator (VCO) is initially selected nominally associated with first synthesized signal frequency, where the VCO is selected from a plurality of n VCOs, and each VCO is tunable across a band of synthesized signal frequencies. A lock detector compares a nominal first synthesized signal frequency to a reference signal frequency. In response to sensing a difference between the nominal first synthesizer and reference signal frequencies, an out-of-lock condition is asserted and a VCO is reselected from the plurality of n VCOs. A mid-point control voltage is supplied to a control voltage input of the reselected VCO. A difference is measured between a mid-point synthesized signal frequency and the reference signal frequency. If the difference is less than a first threshold, the reselected VCO is assigned to generate the first synthesized signal frequency.

Abstract: A system and method are provided for matching a signal (compClk) to a particular frequency band in a multiband communications device. The method accepts a compClk signal, a frequency source is selected from sources collectively covering a range of frequency bands, and a reference clock is supplied from the selected source. If the frequency of the compClk is greater than the reference clock frequency, a high frequency window sampler supplies a first frequency pattern detector output signal (fpdOut—1). Simultaneously, a low frequency window sampler compares the compClk signal with the reference clock. If the frequency of the compClk is less than the reference clock frequency, the low frequency window sampler supplies a second frequency pattern detector output signal (fpdOut—2). The selected frequency source is compared to fpdOut—1 and fpdOut—2 signals, and a determination is made as to whether the selected frequency source coarsely matches the compClk frequency.

Abstract: A window sampling system and method are provided for comparing a signal with an unknown frequency to a reference clock. A pattern modulator accepts a compClk signal and supplies a test window with a period equal to n compClk periods, where n is an integer greater than 1. A pattern detector accepts the test window and a reference clock, and contrasts the test window with the reference clock. In response to failing to fit n reference clock periods inside the test window, the pattern detector supplies a frequency pattern detector output signal (fpdOut) indicating that the frequency of the compClk is greater than the reference clock frequency.