Abstract: Certain aspects of the present disclosure relate to techniques for denoising of physiological signals. A signal (e.g., physiological signal) comprising at least two signal channels can be decomposed (e.g., using independent component analysis (ICA)) into at least two independent components. Then, independent component (IC) denoising can be applied to estimate which of the at least two independent components belong to a signal space and which of the at least two independent components belong to a noise space using a statistical metric associated with the at least two signal channels. A de-noised version of the signal can be generated by preserving in the signal only one or more independent components of the at least two independent components belonging to the signal space.

Abstract: Techniques for efficiently performing full and scaled transforms on data received via full and scaled interfaces, respectively, are described and comprise (1) performing a first transform on a block of first input values to obtain a block of first output values by scaling the block to obtain scaled input values, performing a scaled one-dimensional (1D) transform on each row of the block, and performing a scaled 1D transform on each column of the block; and (2) performing a second transform on a block of second input values to obtain a block of second output values by performing a scaled 1D transform on each row of the block, performing a scaled 1D transform on each column of the block, and scaling the block.

Abstract: Certain aspects of the present disclosure relate to a technique for mitigating artifacts of biophysical signals in a body area network. Information from multiple sensors (including motion information of the body) can be employed in mitigating the artifacts. The biophysical signals in the body area network can be compressively sensed.

Abstract: Certain aspects of the present disclosure relate to a technique for producing a difference value by offsetting a current value of an analog signal with a stored previous value of the analog signal, and generating a digital representation of the difference value. Digital representations obtained by this technique may be sent over a channel to a receiver device for reconstruction of the original analog signal. An integrator of the receiver device may be configured to process (sum) the received samples to generate a reconstructed version of the original signal.

Abstract: Techniques are described to reduce rounding errors during computation of discrete cosine transform using fixed-point calculations. According to these techniques, a discrete cosine transform a matrix of scaled coefficients is calculated by multiplying coefficients in a matrix of coefficients by scale factors. Next, a midpoint bias value and a supplemental bias value are added to a DC coefficient of the matrix of scaled coefficients. Next, an inverse discrete cosine transform is applied to the resulting matrix of scaled coefficients. Values in the resulting matrix are then right-shifted in order to derive a matrix of pixel component values. As described herein, the addition of the supplemental bias value to the DC coefficient reduces rounding errors attributable to this right-shifting. As a result, a final version of a digital media file decompressed using these techniques may more closely resemble an original version of a digital media file.

Abstract: The rate at which data is provided by one device and the rate at which that data is processed by another device may differ. For example, a transmitting device may transmit data according to a transmit clock while a receiving device that receives the transmitted data may process the data according to a receive clock. If there is a timing mismatch between the transmit and receive clocks, the receiving device may receive data faster or slower than it processes the data. In such a case, there may be errors relating to the processing of the received data. To address timing mismatches such as this, the receiving device may delete data from or insert data into the received data. In conjunction with these operations, the receiving device may modify the received data at or near the insertion point or the deletion point in a manner that mitigates any adverse effect the insertion or deletion may have on a resulting output signal.

Abstract: This disclosure describes techniques that can facilitate multimedia telephony. In one example, a method for communication of multimedia data comprises determining a first level of throughput associated with multimedia data communication from a first access terminal to a network, determining a second level of throughput associated with multimedia data communication from the network to a second access terminal based on feedback from the second access terminal to the first access terminal via the network, determining a budget associated with communication of a video unit of the multimedia data, and coding the video unit of the multimedia data based on the budget and the first and second levels of throughput.

Abstract: An apparatus and method for processing signals are disclosed. The apparatus may include an oversampling circuit configured to receive a plurality of audio signal samples, the oversampling circuit being further configured to replicate each of the audio signal samples n times, wherein n is variable.

Abstract: An apparatus and method for communications are disclosed. The apparatus may include an a quantizer having three levels, and a switching power amplifier configured to drive a load having first and second terminals, wherein the switching power amplifier is further configured to switch the first and second terminals between first and second power rails only if the output from the quantizer is at one of the three levels.

Abstract: A technique of spectral noise shaping in an audio coding system is disclosed. Frequency decomposition of an input audio signal is performed to obtain multiple frequency sub-bands that closely follow critical bands of human auditory system decomposition. The tonality of each sub-band is determined. If a sub-band is tonal, time domain linear prediction (TDLP) processing is applied to the sub-band, yielding a residual signal and linear predictive coding (LPC) coefficients of an all-pole model representing the sub-band signal. The residual signal is further processed using a frequency domain linear prediction (FDLP) method. The FDLP parameters and LPC coefficients are transferred to a decoder. At the decoder, an inverse-FDLP process is applied to the encoded residual signal followed by an inverse TDLP process, which shapes the quantization noise according to the power spectral density of the original sub-band signal. Non-tonal sub-band signals bypass the TDLP process.

Abstract: Low latency and computationally efficient techniques may be employed to account for errors in data such as low bit-width, oversampled data. In some aspects these techniques may be employed to mitigate audio artifacts associated with sigma-delta modulated audio data. In some aspects an error may be detected in a set of encoded data based on an outcome of a channel decoding process. Upon determining that a set of data may contain at least one error, the set of data may be replaced with another set of data that is based on one or more neighboring data sets. For example, in some aspects a set of data including at least one bit in error may be replaced with data that is generated by applying a cross-fading operation to neighboring data sets. In some aspects a given data bit may be flipped as a result of a linear prediction operation that is applied to PCM equivalent data that is associated with the given data bit and its neighboring data bits.

Abstract: Certain aspects of the present disclosure relate to techniques for denoising of physiological signals. A signal (e.g., physiological signal) comprising at least two signal channels can be decomposed (e.g., using independent component analysis (ICA)) into at least two independent components. Then, independent component (IC) denoising can be applied to estimate which of the at least two independent components belong to a signal space and which of the at least two independent components belong to a noise space using a statistical metric associated with the at least two signal channels. A de-noised version of the signal can be generated by preserving in the signal only one or more independent components of the at least two independent components belonging to the signal space.

Abstract: In an apparatus and method, time-varying signals are processed and encoded via a frequency domain linear prediction (FDLP) scheme to arrive at an all-pole model. Residual signals resulted from the scheme are estimated and transformed into a time domain signal. Through the process of heterodyning, the time domain signal is frequency shifted toward the baseband level as a downshifted carrier signal. Quantized values of the all-pole model and the frequency transform of the downshifted carrier signal are packetized as encoded signals suitable for transmission or storage. To reconstruct the time-varying signals, the encoded signals are decoded. The decoding process is basically the reverse of the encoding process.

Abstract: A method, apparatus, and system for providing distributed source coding techniques that improve data coding performance, such as video data coding, when channel errors or losses occur. Errors in the reconstruction of the data is eliminated or reduced by sending extra information. Correlation between a predicted sequence and an original sequence can be used to design codebooks and find the cosets required to represent the original image. This information may be sent over another channel, or a secondary channel.

Abstract: A method, apparatus, and system for providing distributed source coding techniques that improve data coding performance, such as video data coding, when channel errors or losses occur. Errors in the reconstruction of the data is eliminated or reduced by sending extra information. Correlation between a predicted sequence and an original sequence can be used to design codebooks and find the cosets required to represent the original image. This information may be sent over another channel, or a secondary channel.

Abstract: Certain aspects of the present disclosure relate to a method for compressed sensing (CS). The CS is a signal processing concept wherein significantly fewer sensor measurements than that suggested by Shannon/Nyquist sampling theorem can be used to recover signals with arbitrarily fine resolution. In this disclosure, the CS framework is applied for sensor signal processing in order to support low power robust sensors and reliable communication in Body Area Networks (BANs) for healthcare and fitness applications.

Abstract: A system and method for media access control are disclosed. The method comprises providing concurrent orthogonal channels to access media using pulse division multiple access to define pulse positions, wherein the pulse division multiple access includes a time hopping sequence and an offset to distinguish the concurrent orthogonal channels. In addition, the method comprises processing signals associated with at least one of the orthogonal channels.

Abstract: Certain aspects of the present disclosure relate to techniques for low-complexity encoding (compression) of broad class of signals, which are typically not well modeled as sparse signals in either time-domain or frequency-domain. First, the signal can be split in time-segments that may be either sparse in time domain or sparse in frequency domain, for example by using absolute second order differential operator on the input signal. Next, different encoding strategies can be applied for each of these time-segments depending in which domain the sparsity is present.

Abstract: Certain aspects of the present disclosure relate to a technique for producing a difference value by offsetting a current value of an analog signal with a stored previous value of the analog signal, and generating a digital representation of the difference value. Digital representations obtained by this technique may be sent over a channel to a receiver device for reconstruction of the original analog signal. An integrator of the receiver device may be configured to process (sum) the received samples to generate a reconstructed version of the original signal.

Abstract: Certain aspects of the present disclosure relate to techniques for measuring body impedance based on baseband signal detection in analog domain. Proposed methods and apparatus are able to measure an impedance of human body based on sub-Nyquist sampling of signals. The proposed techniques can be particularly beneficial for reducing overall sensor power when an actuation signal generates electrical signals corresponding to vital signs in humans.