摘要:
An embodiment of a method and a related apparatus for digital computation of a floating point complex multiply-add is provided. The method includes receiving an input addend, a first product, and a second product. The input addend, the first product and the second product each respectively has a mantissa and an exponent. The method includes shifting the mantissas of the two with smaller exponents of the input addend, the first product, and the second product to align together with the mantissa of the one with largest exponent of the input addend, the first product and the second product, and adding the aligned input addend, the aligned first product and the aligned second product.
摘要:
An embodiment of a method and a related apparatus for digital computation of a floating point complex multiply-add is provided. The method includes receiving an input addend, a first product, and a second product. The input addend, the first product and the second product each respectively has a mantissa and an exponent. The method includes shifting the mantissas of the two with smaller exponents of the input addend, the first product, and the second product to align together with the mantissa of the one with largest exponent of the input addend, the first product and the second product, and adding the aligned input addend, the aligned first product and the aligned second product.
摘要:
An embodiment of a system and method for performing a numerical operation on input data in a hybrid floating-point format includes representing input data as a sign bit, exponent bits, and mantissa bits. The exponent bits are represented as an unsigned integer including an exponent bias, and a signed numerical value of zero is represented as a first reserved combination of the mantissa bits and the exponent bits. Each of all other combinations of the mantissa bits and the exponent bits represents a real finite non-zero number. The mantissa bits are operated on with a “one” bit before a radix point for the all other combinations of the mantissa bits and the exponent bits.
摘要:
An embodiment of a system and method for performing a numerical operation on input data in a hybrid floating-point format includes representing input data as a sign bit, exponent bits, and mantissa bits. The exponent bits are represented as an unsigned integer including an exponent bias, and a signed numerical value of zero is represented as a first reserved combination of the mantissa bits and the exponent bits. Each of all other combinations of the mantissa bits and the exponent bits represents a real finite non-zero number. The mantissa bits are operated on with a “one” bit before a radix point for the all other combinations of the mantissa bits and the exponent bits.
摘要:
Method in a diversity antenna GMSK receiver of determining interference canceling equalizers and corresponding equalizers are described. The method includes providing a plurality of GMSK received signals; de-rotating and splitting each of the plurality of received signals into in phase and quadrature parts to provide a multiplicity of real valued branches; calculating linear equalizers for each of a multiplicity of subsets of the multiplicity of real valued branches; and providing an interference canceling equalizer for each of the multiplicity of real valued branches, each interference canceling equalizer corresponding to a weighted combination of the linear equalizers. A corresponding equalizer includes eight linear equalizers processing four branch signals corresponding to real (I) and quadrature (Q) parts of a GMSK diversity signal from two antennas.
摘要:
A receiver architecture for receiving an FSK signal having a predetermined number of modulation levels includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter bandwidth of about one-half the bandwidth of a pre-modulation filter in a transmitter sending the FSK signal. A discriminator (208) is coupled to the selectivity filter for demodulating the signal. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a maximum likelihood sequence estimation (MLSE) technique utilizing N states for each symbol time, wherein N equals the predetermined number of modulation levels, and wherein templates used in the MLSE for symbol transitions are optimized with a bandwidth substantially less than the bandwidth of the pre-modulation filter.
摘要:
A FCCH Burst detector includes a tone detection filter centered at 67.7 KHz, a tone rejection filter centered at −67.7 KHz, moving average power calculation for the two filter outputs, and a detection logic. A FCCH burst is detected when the ratio of the moving average power of the tone detection filter output to that of the tone rejection filter output is larger than a threshold for a period longer than a threshold. The FB tone end time is detected when the ratio falls back to a threshold or the moving average power of the tone detection filter output falls below a threshold of the average power of the tone detection filter output over a predetermined period. The tone detection filter and the tone rejection filter is implemented by first frequency-shifting the received signal by −67.7 KHz and +67.7 KHz in parallel, then passing the two frequency-shifted signals through two separate low-pass filters.
摘要:
A method for removing direct current (DC) interference from a signal received by a communication receiver is provided that removes both a DC offset signal induced by the communication receiver and transmitter. The method includes removing the estimated DC offset from the received signal, correcting a frequency shift in the received signal, estimating a second DC offset signal induced by a source of the received signal, such as a transmitter and removing the estimated second DC offset from the received signal. The receiver DC offset signal is estimated and removed prior to performing a timing carrier offset correction using Barker code manipulation to remove receiver-induced DC offset interference and to sum all Barker chips after effectively multiplying Barker codes to correlate to a Barker sequence unaffected by the receiver DC offset signal.
摘要:
A timing and carrier error detector module (127) of a communication receiver (111). The timing and carrier error detector module uses phase information of a correlated signal (e.g. a Barker de-spread signal) to generate a timing signal and carrier error signal. In one example, the phase information includes a phase error signal of the correlated signal. In one example, the timing and carrier error detector module calculates an indication of the variance of the phase error signal for a plurality of sample positions over a plurality of Barker symbol intervals. The timing signal is based upon the sample position having a minimum indication of a variance.
摘要:
A synchronization signal includes a plurality of predetermined synchronization symbols shaped by a predetermined symbol pulse. A receiver (100) receives (202) a signal including the synchronization signal, and a processor (106)determines (204) a first plurality of cross-correlations between the predetermined symbol pulse and the received signal. The processor calculates (206) a plurality of sums of products of the plurality of predetermined synchronization symbols and a predetermined subset of the first plurality of cross-correlations. The plurality of sums are mathematically equivalent to a second plurality of cross-correlations between the synchronization signal and the received signal. The processor locates (208) a peak of the plurality of sums to establish receiver synchronization.