Abstract: In some embodiments, an apparatus and a system, as well as methods, include sampling a received signal that represents a downhole signal source, at a sampling frequency and for a sampling duration, to provide a sampled signal. Further activity may comprise detecting a frequency of a component of the sampled signal from inspection of a frequency domain representation of the sampled signal. Further activity may comprise adjusting at least one operating frequency for the downhole tool such that the at least one operating frequency is outside a frequency range from the frequency of the component of the sampled signal. Additional methods, apparatus, and systems are disclosed.

Abstract: A system having a downhole sensor device and a compression device to obtain a sparse representation of data in downhole telemetry applications is described. The downhole sensor device can collect sensor data while the downhole sensor device is within a borehole. The compression device is coupled to the downhole sensor device and configured to receive the sensor data. The compression device can determine a wavelet coefficient vector for at least one row of n-tuple vectors. The wavelet coefficient vector can have a sparse representation of one or more nonzero elements. The compression device can process the wavelet coefficient vector through a set of compression algorithms, and determine a minimal bit cost of the processed wavelet coefficient vector. The compression device can select a compression algorithm from the set of compression algorithms corresponding to the minimal bit cost. The compression device can generate compressed data based on the selected compression algorithm.

Abstract: In some embodiments, an apparatus and a system, as well as methods, include sampling a received signal that represents a downhole signal source, at a sampling frequency and for a sampling duration, to provide a sampled signal. Further activity may comprise detecting a frequency of a component of the sampled signal from inspection of a frequency domain representation of the sampled signal. Further activity may comprise adjusting at least one operating frequency for the downhole tool such that the at least one operating frequency is outside a frequency range from the frequency of the component of the sampled signal. Additional methods, apparatus, and systems are disclosed.

Abstract: In some examples, a drillstring includes a plurality of drill pipe sections that are coupled together by a drill pipe joint section structure. The drill pipe sections and the drill pipe joint section structure are acoustically impedance matched. In another example, the drill pipe sections comprise a plurality of different pipe lengths, those lengths being different than a length of the drill pipe joint section structure. A drillstring is constructed of these different lengths of drill pipe and drill pipe joint section structures in a non-periodic manner or random sequence. In another example, the drill pipe sections and drill pipe joint section structure comprise materials having substantially similar acoustic properties.

Abstract: A system having a downhole sensor device and a compression device to obtain a sparse representation of data in downhole telemetry applications is described. The downhole sensor device can collect sensor data while the downhole sensor device is within a borehole. The compression device is coupled to the downhole sensor device and configured to receive the sensor data. The compression device can determine a wavelet coefficient vector for at least one row of n-tuple vectors. The wavelet coefficient vector can have a sparse representation of one or more nonzero elements. The compression device can process the wavelet coefficient vector through a set of compression algorithms, and determine a minimal bit cost of the processed wavelet coefficient vector. The compression device can select a compression algorithm from the set of compression algorithms corresponding to the minimal bit cost. The compression device can generate compressed data based on the selected compression algorithm.

Abstract: In some examples, a drillstring includes a plurality of drill pipe sections that are coupled together by a drill pipe joint section structure. The drill pipe sections and the drill pipe joint section structure are acoustically impedance matched. In another example, the drill pipe sections comprise a plurality of different pipe lengths, those lengths being different than a length of the drill pipe joint section structure. A drillstring is constructed of these different lengths of drill pipe and drill pipe joint section structures in a non-periodic manner or random sequence. In another example, the drill pipe sections and drill pipe joint section structure comprise materials having substantially similar acoustic properties.

Abstract: An audio processing system comprising two or more microphones and an echo cancellation system configured to apply a fast converging adaptive filtering algorithm to low frequency bands of a first microphone signal to generate first synthesized echo signal components and an adaptive filtering algorithm to high frequency bands of the first microphone signal to generate second synthesized echo signal components and to apply the first synthesized echo signal components and the second synthesized echo signal components to the first microphone signal to cancel an echo signal of the first microphone signal. An echo estimate and suppression system is configured to receive the first synthesized echo signal components and the second synthesized echo signal components and to apply them to estimate powers of echo signals in one or more additional microphones.