Abstract: A method and apparatus for generating harmonics using polynomial non-linear functions. Polynomial functions are used to produce harmonics of an input signal up to a predetermined order, and that match a preferred set of characteristics. The preferred characteristics include approximating a sine function to generate odd harmonics, and using a function with zero slope at ?1, 0, and +1 to generate even harmonics. The polynomial coefficients may be chosen such that most of the coefficients for the odd polynomial function are scaled by the same constant as the coefficients for the even polynomial function, so that the calculation is shared between the two polynomials. In one embodiment, a digital signal processor having a pipelined ALU and a MAC is used to calculate the desired polynomial non-linear functions.

Abstract: A ternary pulse width modulation (“PWM”) method and apparatus. In one embodiment, the start of the pulse sequence in the “current” frame is referenced to the end of the pulse sequence in a previous, “reference” frame, rather than to the frame boundary at the start of the current frame, thereby allowing the compensation portion of the pulse sequence to overlap into the preceding or following frame, thus achieving a higher modulation index without dropping the compensation pulses. Although in most instantiations, the reference frame will be the frame immediately preceding in time the current frame, in other instances, the reference frame may be any frame preceding the current frame that falls within the constraints of the timing facility.

Abstract: A pipelined decimation in frequency FFT butterfly method, and an apparatus to perform this method comprising: a data memory with at least one read port and one write port; an add/subtract unit receiving data from the memory; a multiply/accumulate unit receiving data from the add/subtract unit; a source of coefficients, from logic gates or a coefficient memory, to supply FFT twiddle factors to the multiply/accumulate unit; a shifter receiving data from at least one of the add/subtract unit and the multiply/accumulate unit, the shifter supplying data to the write port of the data memory; wherein the apparatus performs these calculations in four cycles of the add/subtract unit and in four cycles of the multiply/accumulate unit, using complex arithmetic.

Abstract: A ternary pulse width modulation (“PWM”) method and apparatus. In one embodiment, the start of the pulse sequence in the “current” frame is referenced to the end of the pulse sequence in a previous, “reference” frame, rather than to the frame boundary at the start of the current frame, thereby allowing the compensation portion of the pulse sequence to overlap into the preceding or following frame, thus achieving a higher modulation index without dropping the compensation pulses. Although in most instantiations, the reference frame will be the frame immediately preceding in time the current frame, in other instances, the reference frame may be any frame preceding the current frame that falls within the constraints of the timing facility.

Abstract: A sample rate converter for an oversampled data stream develops interpolated samples at a first oversample rate, from samples at a second oversample rate; wherein the first oversample rate is a non-integer multiple of the second oversample rate. When the samples at the second oversample rate are changing state, at least two interpolated samples are generated or the interpolation is at least second order. When the sample at the second oversample rate is not changing state, the sample at the second oversample rate is passed substantially unchanged. In one embodiment of the invention, asynchronous sample rate conversion is performed, and the first oversample rate is a varying non-integer multiple of the second oversample rate.

Abstract: A pipelined decimation in frequency FFT butterfly method, and an apparatus to perform this method comprising: a data memory with at least one read port and one write port; an add/subtract unit receiving data from the memory; a multiply/accumulate unit receiving data from the add/subtract unit; a source of coefficients, from logic gates or a coefficient memory, to supply FFT twiddle factors to the multiply/accumulate unit; a shifter receiving data from at least one of the add/subtract unit and the multiply/accumulate unit, the shifter supplying data to the write port of the data memory; wherein the apparatus performs these calculations in four cycles of the add/subtract unit and in four cycles of the multiply/accumulate unit, using complex arithmetic.

Abstract: A method and apparatus for generating harmonics using polynomial non-linear functions. Polynomial functions are used to produce harmonics of an input signal up to a predetermined order, and that match a preferred set of characteristics. The preferred characteristics include approximating a sine function to generate odd harmonics, and using a function with zero slope at ?1, 0, and +1 to generate even harmonics. The polynomial coefficients may be chosen such that most of the coefficients for the odd polynomial function are scaled by the same constant as the coefficients for the even polynomial function, so that the calculation is shared between the two polynomials. In one embodiment, a digital signal processor having a pipelined ALU and a MAC is used to calculate the desired polynomial non-linear functions.

Abstract: A sample rate converter for an oversampled data stream develops interpolated samples at a first oversample rate, from samples at a second oversample rate; wherein the first oversample rate is a non-integer multiple of the second oversample rate. When the samples at the second oversample rate are changing state, at least two interpolated samples are generated or the interpolation is at least second order. When the sample at the second oversample rate is not changing state, the sample at the second oversample rate is passed substantially unchanged. In one embodiment of the invention, asynchronous sample rate conversion is performed, and the first oversample rate is a varying non-integer multiple of the second oversample rate.

Abstract: A system includes a decimation module having an adjustable decimation rate and a filter module responsive to the decimation module. A digital phase lock loop is operable to control a decimation rate of the decimation module. The decimation module is a cascade integrator comb decimation module.

Abstract: A system includes a decimation module having an adjustable decimation rate and a filter module responsive to the decimation module. A digital phase lock loop is operable to control a decimation rate of the decimation module. The decimation module is a cascade integrator comb decimation module.

Abstract: A system includes a decimation module having an adjustable decimation rate and a filter module responsive to the decimation module. A digital phase lock loop is operable to control a decimation rate of the decimation module. The decimation module is a cascade integrator comb decimation module.

Abstract: A system includes a decimation module having an adjustable decimation rate and a filter module responsive to the decimation module. A digital phase lock loop is operable to control a decimation rate of the decimation module. The decimation module is a cascade integrator comb decimation module.

Abstract: A system and method for decimating a digital signal is disclosed. The system includes an input to receive digital data, a control input to receive a desired decimation rate, and an integrator stage responsive to the input. The system also includes a variable rate down sampling module responsive to the integrator stage and a differentiator stage responsive to the variable rate down sampling module. The down sampling module has a decimation rate that is dynamically adjustable based on the desired decimation rate.

Abstract: A system and method for using one or more clock signals is disclosed. The system includes a clock translator that has a first input to receive a first reference clock signal and a second input to receive a second reference clock signal. The clock translator also includes an output to provide a bit rate clock signal having a clock frequency in a first ratio with respect to the frequency of the first reference clock but having a resolution based on at least a portion of the second reference clock signal. The second reference clock has a faster rate than the first reference clock.

Abstract: A system and method for determining a clock rate of a digital phase lock loop is disclosed. The system includes a first input to receive a first clock signal, an output to provide a second clock signal, and a dividerless initial clock rate determination module to calculate an initial clock rate value based on an reciprocal of a pulse length of the first clock signal. In a particular embodiment, the dividerless initial clock rate determination module performs a piecewise linear operation to calculate the initial clock rate value.

Abstract: A system and method for using one or more clock signals is disclosed. The system includes a clock translator that has a first input to receive a first reference clock signal and a second input to receive a second reference clock signal. The clock translator also includes an output to provide a bit rate clock signal having a clock frequency in a first ratio with respect to the frequency of the first reference clock but having a resolution based on at least a portion of the second reference clock signal. The second reference clock has a faster rate than the first reference clock.

Abstract: A system and method for using one or more clock signals is disclosed. The system includes a clock translator that has a first input to receive a first reference clock signal and a second input to receive a second reference clock signal. The clock translator also includes an output to provide a bit rate clock signal having a clock frequency in a first ratio with respect to the frequency of the first reference clock but having a resolution based on at least a portion of the second reference clock signal. The second reference clock has a faster rate than the first reference clock.