Abstract: A communication system that transfers digital data on a fixed frequency channel of a radio frequency band in the presence of interference from at least one FHSS interference source includes a time diversity generation circuit. The time diversity circuit compacts a duration of data frames then replicate the time compressed data frames. The duplicated time compressed frames of data are transmitted to a communication receiver that has a time diversity data recovery circuit. The time diversity data recovery circuit buffers the received compressed and replicated data frames, evaluates whether each of the duplicated time compressed data frames are received correctly. If any one of the duplicated time compressed data frames is destroyed, the copy of the destroyed duplicated time compressed data frame is used to recover the data frame.

Abstract: A receiver system that receives and recovers digital data on a fixed frequency channel of a radio frequency band in the presence of interference from at least one FHSS interference source. The digital data has a duration of data frames compacted then replicated to form duplicated time compressed data frames. The duplicated time compressed frames of data are transmitted to a communication receiver that has a time diversity data recovery circuit. The time diversity data recovery circuit buffers the received compressed and replicated data frames, evaluates whether each of the duplicated time compressed data frames are received correctly. If any one of the duplicated time compressed data frames is destroyed, the copy of the destroyed duplicated time compressed data frame is used to recover the data frame.

Abstract: A transmitter system that transfers digital data on a fixed frequency channel of a radio frequency band in the presence of interference from at least one FHSS interference source includes a time diversity generation circuit. The time diversity circuit compacts a duration of data frames then replicate the time compressed data frames. The duplicated time compressed frames of data are transmitted to a communication receiver that has a time diversity data recovery circuit.

Abstract: A communication system compensates pulse positioned modulated data signals for channel induced intersymbol interference and extracts pulse positioned encoded data from a received signal corrupted with the channel induced intersymbol interference. The communication system has a transmitter and a receiver. The transmitter includes a modulation apparatus that has a symbol mapping circuit, which receives data symbols to be transmitted and maps the data symbols to a transmission code. The receiver has a demodulation apparatus to recover data symbols in the presence of the channel induced intersymbol interference. The demodulation apparatus has a sampling circuit in communication with a signal receiving circuit within the receiver to sample at a regular period received data symbols acquired by the receiving circuit. The samples of the data samples are retained by a sample retaining circuit in communication with the sampling circuit.

Abstract: A diversity receiver system applying diversity to improve reception of coded data in presence of fading of the broadcast signal. The communication system includes a diversity receiver system receiving the coded data modulated broadcast signal from a transmission channel. The diversity receiver system has a signal acquisition device for evaluation of the signal characteristics of copies of the coded data modulated broadcast signal, extracting the coded data, control signals, and locking signals from the copies of the coded data. A diversity circuit selects one of the copies of the coded data modulated broadcast signals. An error evaluation circuit evaluates the coded data signal for errors and provides an error signal to the diversity circuit indicating an error state of the selected data, wherein the diversity circuit selects a second copy of the coded data modulated broadcast signal.

Abstract: A system for transmitting digitized samples of analog signals while concealing unrecoverable digitized samples of analog signals to maintain a level of fidelity in reproducing the analog signals. The digitized samples of the analog signals are burst transmitted such that the probability of interference with the transmission and thus corruption of the digitized samples of the analog signals is minimized. The digitized samples are received without synchronizing a receiving clock with a transmitting clock to capture the digitized samples of the analog signals. The digitized samples are converted from various sampling rates to digitized samples of the analog signals having a rate. Any large groups of digitized samples that are in error or corrupted in transmission are softly muted to avoid annoying clicks. Any long term difference between a transmit clock and a receive clock is tracked and the digitized samples are interpolated or decimated to eliminate any underrun or overrun of the digitized samples.

Abstract: Described is a personal on-demand audio entertainment system with a base unit attached to a personal computer or other source, a headphone unit and a remote control unit. The base unit transmits digital audio content to the headphone unit using infrared, radio frequency, magnetic or electromagnetic coupling. These data are stored in solid-state memory within the headphone unit. In the headphone unit, the stored digital audio content is converted to analog audio signals, amplified and sent to transducers for conversion to audio signal for the listener during playback. The system is designed such that playback may occur during the downloading process. The remote control unit also uses infrared, radio frequency, magnetic or electromagnetic coupling for communication to the headphone unit. This communication is made using a different channel and does not interfere with the audio data downloading.

Abstract: It is the objective of this invention to provide a multichannel digital filter bank circuit and a method implemented by cascading sub-filters of the recursive type suitable for graphically equalizing electrical signals received via a communication path. It is also an objective of this invention to produced equalized signals having minimal distortion of signal spectral characteristics including magnitude and phase. The circuit of this invention is implemented with cascaded connections of first order or second order digital filters. It is an additional objective of this invention to provide for the programming of the individual transfer functions of the above digital filters so as to produce unity gain. This unity gain case results in an output signal which is an exact replica of the input signal with no delay. This result indicates the minimal distortion introduced by the method of this invention.

Abstract: A system for transmitting, receiving, recovering, and reproducing digitized samples of analog signals while concealing unrecoverable digitized samples of analog signals to maintain a level of fidelity in reproducing the analog signals. The digitized samples of the analog signals are burst transmitted such that the probability of interference with the transmission and thus corruption of the digitized samples of the analog signals is minimized. The digitized samples are received without synchronizing a receiving clock with a transmitting clock to capture the digitized samples of the analog signals. The digitized samples are converted from various sampling rates to digitized samples of the analog signals having a rate. Any large groups of digitized samples that are in error or corrupted in transmission are softly muted to avoid annoying clicks.

Abstract: Described is a device and method using an interactive process to improve the listening experience for a user of headphones or hearing aids. The system uses a sound source such as a PC or similar device. Programming of the headphone or hearing aid is accomplished using a process delivered by the sound source. The user is prompted to listen to various signals thereby testing the frequency response of each ear and headphone combination. Once the user testing is completed, individualized compensation coefficients are created to optimize the listening experience for the user. The coefficients would be downloaded to and stored within the hearing aids. Downloading could accomplished by wire or by wireless means such as infrared, radio frequency, magnetic or electromagnetic coupling. In headphone units, the compensation factors could be stored either within the headphones or maintained at the sound source.

Abstract: Described is a personal on-demand audio entertainment system with a base unit attached to a personal computer or other source, a headphone unit and a remote control unit. The base unit transmits digital audio content to the headphone unit using infrared, radio frequency, magnetic or electromagnetic coupling. These data are stored in solid-state memory within the headphone unit. In the headphone unit, the stored digital audio content is converted to analog audio signals, amplified and sent to transducers for conversion to audio signal for the listener during playback. The system is designed such that playback may occur during the downloading process. The remote control unit also uses infrared, radio frequency, magnetic or electromagnetic coupling for communication to the headphone unit. This communication is made using a different channel and does not interfere with the audio data downloading.