摘要:
A stabilized quadrature oscillator providing consistently high signal quality is disclosed. The stabilized quadrature oscillator includes an iterative quadrature oscillator and a quadrature signal stabilizer. The iterative quadrature oscillator generates an iterative cosine signal and an iterative sine signal using a stabilized cosine signal and a stabilized sine signal from the quadrature signal stabilizer. The quadrature signal stabilizer generates the stabilized cosine signal and the stabilized sine signal based on an energy measure of the iterative cosine signal and the iterative sine signal. Specifically, if the energy measure is less than a low threshold then the quadrature signal stabilizer generates the stabilized sine signal and the stabilized cosine signal to have a greater magnitude than the iterative sine signal and the iterative cosine signal, respectively. Conversely, if the energy measure is greater than a high threshold then the quadrature signal stabilizer generates the stabilized sine signal and the stabilized cosine signal to have a lesser magnitude than the iterative sine signal and the iterative cosine signal, respectively.
摘要:
A stabilized quadrature oscillator providing consistently high signal quality is disclosed. The stabilized quadrature oscillator includes an iterative quadrature oscillator and a quadrature signal stabilizer. The iterative quadrature oscillator generates an iterative cosine signal and an iterative sine signal using a stabilized cosine signal and a stabilized sine signal from the quadrature signal stabilizer. The quadrature signal stabilizer generates the stabilized cosine signal and the stabilized sine signal based on an energy measure of the iterative cosine signal and the iterative sine signal. Specifically, if the energy measure is less than a low threshold then the quadrature signal stabilizer generates the stabilized sine signal and the stabilized cosine signal to have a greater magnitude than the iterative sine signal and the iterative cosine signal, respectively. Conversely, if the energy measure is greater than a high threshold then the quadrature signal stabilizer generates the stabilized sine signal and the stabilized cosine signal to have a lesser magnitude than the iterative sine signal and the iterative cosine signal, respectively.
摘要:
One or more processing units confirm existence of narrow band interference in a signal by using an estimate f of the frequency, to check for one or more harmonics. In illustrative embodiments, the estimate f is automatically identified as a second harmonic if a predetermined criterion is satisfied by the signal (in the frequency domain) at either of two frequencies namely (A) frequency f/2 and (B) frequency (M−f)/2 and whichever of these two frequencies is stronger is identified as the fundamental frequency. In several such embodiments, the estimate f is automatically identified as a third harmonic if a predetermined criterion is satisfied by the signal (in the frequency domain) at any of three frequencies namely (C) frequency f/3 and (D) frequency (M−t)/3 and (E) frequency (M+f)/3. If the predetermined criteria are not met at all five frequencies (A)-(E) then f is identified as the fundamental frequency.
摘要:
One or more processing units confirm existence of narrow band interference in a signal by using an estimate f of the frequency, to check for one or more harmonics. In illustrative embodiments, the estimate f is automatically identified as a second harmonic if a predetermined criterion is satisfied by the signal (in the frequency domain) at either of two frequencies namely (A) frequency f/2 and (B) frequency (M−f)/2 and whichever of these two frequencies is stronger is identified as the fundamental frequency. In several such embodiments, the estimate f is automatically identified as a third harmonic if a predetermined criterion is satisfied by the signal (in the frequency domain) at any of three frequencies namely (C) frequency f/3 and (D) frequency (M−t)/3 and (E) frequency (M+f)/3. If the predetermined criteria are not met at all five frequencies (A)-(E) then f is identified as the fundamental frequency.
摘要:
One or more processing units are programmed to select from among M tones in a frequency domain representation of a signal, a set of tones including at least a strongest tone (relative to background noise) and a tone adjacent thereto. From among M complex numbers in the frequency domain representation of the signal, a set of complex numbers are identified and denoted as a vector Z, corresponding to the selected set of tones. Vector Z is then multiplied with each of M columns of a matrix G which is predetermined to identify a sub-resolution maxima in Z. The M products that result from the vector multiplication of Z and G are used to determine and store in memory at least one or both of: (A) a flag indicating presence or absence of narrowband interference in the signal; and (B) an estimate of a frequency of the narrowband interference.
摘要:
A decoder includes circuitry for generating bits representing received signals, and beliefs representing an associated reliability of each bit. A bit node computation block receives the bits and associated beliefs, and generates a plurality of bit node messages. A plurality of M serially-connected pipeline stages receive the bit node messages and after M decoding cycles, and generate a plurality of check node messages once per decoding cycle, wherein for each iteration cycle, each of the M serially-connected pipeline stages performs check node computations using all of J component codes, wherein each one of the M serially-connected pipeline stages performs check node computations once per decoding cycle using a single component code that is different that component codes used for all other of the M serially-connected pipeline stages, wherein J is at least as great as M, and wherein each iteration includes M decoding cycles.
摘要:
Methods and systems for multi-input IIR filters with error feedback are disclosed. By using multiple-inputs to generate multiple outputs during each iteration, a multi-input IIR filter in accordance with the present invention has greatly increased throughput. Furthermore, the addition of a multi-variable error feedback unit in accordance with the present invention in a multiple-input IIR filter can greatly increase the accuracy of the multi-variable IIR Filter.
摘要:
Embodiments of a method and apparatus for reducing non-linear transmit signal components of a receive signal of a transceiver signal are disclosed. The method includes the transceiver simultaneously transmitting a transmit signal, and receiving the receive signal. A non-linear replica signal of non-linear transmission signal components that are created in the transceiver by a transmit signal DAC, and imposed onto the receive signal, is generated. The non-linear replica signal is subtracted from the received signal reducing the non-linear transmission signal components imposed onto the receive signal.
摘要:
A communications receiver and method are provided for receiving a transmitted signal from a transmission channel having a low-pass filter characteristic. The receiver includes a receiver input for coupling to the channel and a switched capacitor pre-emphasis filter coupled to the receiver input. An analog-to-digital (A/D) converter is coupled to an output of the pre-emphasis filter. An equalizer is coupled to an output of the analog-to-digital converter.
摘要:
Embodiments of a method and apparatus for generating an estimated non-linear echo signal are disclosed. One method includes receiving a plurality of data inputs. The plurality of data inputs are partitioned into subsets. A weight vector is computed for each of the subsets. A vector of addresses to memory locations is computed for each of the subsets. Values of interpolants are accessed at the memory locations (interpolation sites) based on the vector of addresses for each of the subsets. The estimated non-linear echo signal based is calculated on the values of the interpolants and the weight vector corresponding to each subset.