Patent application number | Description | Published |
20090213943 | TIME AND FREQUENCY DOMAIN BASED APPROACHES FOR FINE TIMING AND FREQUENCY ESTIMATIONS IN ISDB-T AND ISDB-TSB RECEIVER DESIGN - A method and apparatus for estimating timing and frequency offsets in an ISDB-T and ISDB-TSB receiver. In different embodiments, the method comprises estimating timing and frequency offsets by different estimation processes; assigning weights to the timing and frequency offsets according to the channel condition; and calculating timing and frequency offsets using the estimates of timing and frequency offsets and the weights. | 08-27-2009 |
20090232256 | ITERATIVE DECODING FOR LAYER CODED OFDM COMMUNICATION SYSTEMS - A modified classical Viterbi decoder which can take extrinsic information and output hard decisions. A modified Viterbi decoder is provided comprising a branch metric unit, the unit having a calculator; and a processor adapted to compute a revised branch metric by combining the initial branch metric and an additional weight parameter. The modified classical Viterbi decoder computes a branch metric by summing an initial branch metric and the additional weight parameter. | 09-17-2009 |
20090232264 | LOW COMPLEXITY HIGH PERFORMANCE TMCC ACQUISITION IN ISDB-T AND ISDB-TSB RECEIVERS - A method of TMCC information acquisition in an ISDB-T/TSB receiver comprises detecting coarse frequency offset in the receiver to identify bins that have TMCC information; and acquiring TMCC and symbol number information from the identified bins. The detecting process may be conducted using different methods and the acquiring process may be conducted using different methods. The TMCC information acquisition method saves memory space and provides enhanced performance by using coarse frequency offset to identify the bins that have TMCC information and obtaining the TMCC and symbol number information from the identified bins. | 09-17-2009 |
20090252262 | SYMMETRIC PILOT PROCESSING FOR ROBUST TIMING OFFSET AND FREQUENCY OFFSET ESTIMATION IN ISDB-T AND ISDB-TSB RECEIVERS - Timing and frequency offset processing in sub-carriers is performed in an Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) receiver system. Sub-carriers are divided into two sub-sets, where the sub-sets contain an equal number of sub-carriers. Subsequently bad sub-carriers are removed, if present, from first sub-set of the sub-sets, and corresponding sub-carriers from a second sub-set of the sub-sets are also removed. Further, a phase difference on each sub-carrier from each sub-set is computed, and mean phase differences of each of the sub-sets are computed. Furthermore, frequency offset is computed by averaging the mean phase differences of the sets. | 10-08-2009 |
20090252263 | ESTIMATING DOPPLER FREQUENCY IN ISDB-T SYSTEMS - A technique for estimating maximum Doppler frequency of a wireless signal in a wireless communication system, wherein the method comprises receiving a wireless signal; determining an impulse response of the received wireless signal; determining an auto-correlation function (ACF) value of the impulse response of the received wireless signal; determining a power spectrum density of said received wireless signal based on the ACF value; and selecting an algorithm for performing demodulation of the received wireless signal by utilizing the determined power spectrum density. | 10-08-2009 |
20090262842 | Robust FFT Trigger Point Tracking for Echo Channels in OFDM Based Communication Systems - Identifying a trigger point of at least one OFDM decoder includes correlating a first time-domain sample of the at least one OFDM symbol with a second time-domain sample of the at least one OFDM symbol, processing the first time-domain sample and the second time-domain sample in the first moving average filter to determine a channel impulse response, comparing at least one correlation value of a first biggest path in the channel impulse response and a second biggest path in the channel impulse response, and determining a channel length of the channel impulse response based on a time duration of the channel impulse response. The OFDM decoder includes a first moving average filter and a second moving average filter. | 10-22-2009 |
20090268735 | Look-Up Table Based Approach for Layer Combining in ISDB-T and ISDB-TSB Receivers - A method of layer combining based on generating a look-up table in an Integrated Services Digital Broadcasting (ISDB) receiver includes obtaining a transmission parameter configuration, generating the look-up table based on the transmission parameter configuration, assembling a null transport stream packets and a valid transport stream packets from a plurality of layers of a multiplexing frame, and generating a completed transport packet stream using the look-up table. The receiver may generate the look-up table by at least one of generating the look-up table in real time or selecting from a look-up table set based on the transmission parameter configuration. The transmission parameter configuration may include at least one of a transmission mode, a guard interval, a modulation, and a coding rate. The look-up table may define an order of the null transport stream packets and the valid transport stream packets from the plurality of layers in the multiplexing frame. | 10-29-2009 |
20090268826 | Time Domain Based Approach for Fast Fading Channel FFT Trigger Point Tracking in ISDB Receivers - A method of fast fading channel Fast Fourier Transform (FFT) trigger point tracking in an integrated services digital broadcasting (ISDB) receiver includes inputting a signal in a fading channel including N Orthogonal Frequency Division Multiplexing (OFDM) symbols, determining an average correlation result of a current time-domain sample of the signal and a previous time-domain sample taken previously of the signal, accumulating the average correlation result for at least one of the OFDM symbols, determining a peak of the average correlation result to obtain a peak position, and identifying the peak position as a trigger point of the input signal. The peak position may be compared with a first trigger point to generate a trigger point error signal. The first trigger point may be set at the middle of a guard of an OFDM symbol to generate the trigger point error signal. | 10-29-2009 |
20090268850 | Coarse Frequency Offset Estimation in ISDB Receivers - A method of estimating a coarse frequency offset in a receiver includes providing at least one candidate frequency offset in Orthogonal Frequency-Division Multiplexing (OFDM) symbols having transmission and multiplexing configuration control (TMCC) bins and auxiliary channel (AC) bins, modulating the TMCC bins and AC bins using differential binary phase shift keying (DBPSK) modulation, estimating a phase difference between a first symbol and a second symbol for the candidate frequency offset of the TMCC and AC bins to obtain a resulting phase difference, correcting the resulting phase difference based on a difference between the candidate frequency offset and a Fast Fourier Transform (FFT) center bin to obtain a corrected phase difference, mapping the corrected phase difference to numeric numbers, and adding the numeric numbers for the candidate frequency offset to obtain a summation result. The numeric numbers correspond to at least one of +1 or −1. | 10-29-2009 |
20090285314 | ADAPTIVE FREQUENCY DOMAIN EQUALIZATION IN OFDM BASED COMMUNICATION SYSTEM - An apparatus, system, and method of performing adaptive frequency domain equalization in an Orthogonal Frequency Domain Multiplexing (OFDM) based communication system transmitting data information, wherein the method comprises receiving OFDM symbols comprising scattered pilots; obtaining channel estimates on every third bin of the scattered pilots in a frequency domain, wherein the channel estimates are obtained by performing an interpolation in a time domain across the received OFDM symbols; estimating an original channel based on the channel estimates, wherein the original channel in the time domain is estimated by applying a finite impulse response (FIR) low-pass filter in a frequency domain, wherein the FIR low-pass filter is adaptive according to a delay span of an original channel impulse response and is sufficiently wide to cover the delay span of the original channel impulse response; and dividing the received OFDM symbols by the channel estimate to obtain transmitted data information. | 11-19-2009 |
20090296843 | SEGMENTED-FRAME SYNCHRONIZATION FOR ISDB-T AND ISDB-TSB RECEIVER - A technique for segmented frame synchronization for Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) and Integrated Services Digital Broadcasting-Terrestrial Sound Broadcasting (ISDB-TSB) systems, wherein the method comprises receiving a wireless digital signal comprising an Orthogonal Frequency Division Multiplexing (OFDM) frame, further comprising ODFM symbols, in a receiver and wherein the receiver comprises a time de-interleaver, a bit de-interleaver, and a descrambler; filling memory of time de-interleaver and bit de-interleaver by the received wireless digital signal; determining an OFDM segmented frame boundary when memory of the time de-interleaver and bit de-interleaver are full; decoding bits from time de-interleaver and bit de-interleaver using a Viterbi decoder; outputting the Viterbi decoding bits from time de-interleaver and bit de-interleaver when the OFDM segmented frame boundary is detected; obtaining a segmented multiplexing frame boundary upon receipt of the first bit from the Viterbi decoder; and synchronizing the OFDM frame based on the segmented multiplexing frame boundary. | 12-03-2009 |
20100260245 | System and method for low-power echo and next cancellers - A method to design low complexity and low power echo and NEXT cancellers based on wordlength reduction technique is presented. A circuit architecture to implement echo and cancellers is also presented. The low complexity and low power design relies on the fact that a TH precoder can be viewed as an IIR filter with an input equal to the sum of the original input to the TH precoder and a compensation signal. The proposed design also relies on the fact that sum of the original input to the TH precoder and the compensation signal has finite levels, which can be represented in less bits than the original input of the echo and NEXT cancellers. An improved design by exploiting the statistics of the compensation signal is also proposed to further bring down the complexity and power consumption of these cancellers. | 10-14-2010 |
20110249180 | Dual Burst Locked Oscillator Architecture for an Analog Television Receiver - Color information decoding on a composite video signal that includes modulated color information for an analog television receiver. A first burst locked oscillator (BLO) operates in a first loop gain, and a second BLO operates in second loop gain and is operatively connected to the first BLO. The first loop gain is higher than the second loop gain. A method includes receiving, in a first burst accumulator, mixed down color information directly from a first phase detector without filtering the mixed down color information, converting the composite video signal to a burst gate signal, accumulating one or more of the burst gate signal, and calculating a frequency offset for the second BLO in the first BLO expedite the calculating of the frequency offset and to compensate for the second BLO operating in the second gain loop. | 10-13-2011 |
20110249182 | SECAM Line Identification and PAL Switch - SECAM line identification in an analog television includes an accumulator that accumulates a FM demodulated output corresponding to a color reference tone for each SECAM line; a first leakage average filter receiving a first result from the accumulator; a second leakage average filter receiving a second result from the accumulator; and a line decision block comparing the first result and the second result. An apparatus for soft-decision based PAL switch detection in an analog television includes a burst locked oscillator (BLO) receiving a composite video signal as input and producing an instantaneous PAL switch signal for each line; a leakage average filter receiving the PAL switch signal and filtering noise from an output received from the BLO; and a switch detection block receiving a filtered output from the leakage average filter, and making a decision based on a sign of the filtered output of the leakage average filter. | 10-13-2011 |
20110250859 | Pilot Based Adaptation for FM Radio Receiver - Performing a decoding mode of a frequency modulation (FM) signal for an adaptive FM radio receiver includes passing the FM signal through a FM demodulator to obtain a composite signal that includes a pilot signal and noise around the pilot signal, passing the composite signal through a band bass filter, filtering the pilot signal from the noise using a pilot and noise separator that includes a notch filter that filters the pilot signal from the noise, obtaining average amplitudes of the pilot signal and the noise, comparing a ratio between the average amplitudes of the pilot signal and the noise with a programmable threshold, and selecting a decoding mode and an audio low pass filter. The decoding mode is selected based on a quality of the pilot signal being decoded and the audio LPF is selected based on the comparison ratio. | 10-13-2011 |
20110255011 | All Digital Front-End Architecture for Television with Sigma-Delta ADC Input - A digital front-end architecture for television receivers with sigma-delta ADC input. An input digital signal is fed to the architecture and the gain is controlled by a gain stage. In the first method, the gain stage is controlled by a first AGC. Here, the gain is increased if the first threshold value is larger than the magnitude of a complex phase-locked loop (CPLL) output, and the gain is decreased if the first threshold value is lower than the magnitude of the CPLL output. In the second method, the gain is controlled through a second AGC. The gain is controlled by increasing the gain if the second threshold value is larger than a line peak of the moving average filter output, and the gain is decreased if the second threshold value is lower than the peak. The second threshold value and the peak are compared in a peak search block. | 10-20-2011 |