Thomson Licensing S.a.

Thomson Licensing

Zhiming Zhang

Chandra Mohan

Manuel Apraez

Michael D Zoltowski

Jayanta Majumdar

Wilhelm Ernst Riedl

James Vincent Krogmeier

Gregory John Tomezak

An FM broadcast transmitter transmits a broadcast signal having a carrier at a broadcast frequency and sidebands, able to be transmitted at full power, within a transmission bandwidth around the carrier. It includes a source of a modulated FM stereo signal having a carrier at the broadcast frequency and having sidebands with a bandwidth less than the transmission bandwidth representing a stereo signal. It also includes a source of a modulated in-band-on-channel (IBOC) signal, having carrier pulses spaced relative to each other to represent the IBOC digital data signal encoded as a variable pulse width encoded signal, and a bandwidth within the transmission bandwidth not overlapping the FM stereo signal sidebands. A signal combiner combines the modulated FM stereo signal and the modulated IBOC signal to form the broadcast signal.

In-band-on-channel broadcast system for digital data

Variable Aperture Coded (VAC) signals for VAC modulation are advantageously generated by a digital signal processor () that yields a VAC signal having a single narrow peak in the positive frequency region. A Discrete-Time Hilbert transformer () isolates only the positive spectral peaks, thus yielding a VAC signal that affords greater control over zero crossings.

DSP-based variable aperture code generation technique

A digital data modulator is coupled to a source of a digital data signal. An encoder encodes the digital data using a variable pulse width code. A pulse signal generator generates pulses representing edges of the encoded digital data signal. A carrier signal generator generates a carrier signal having carrier pulses corresponding to the pulses from the pulse signal generator. A corresponding digital data demodulator is coupled to a source of a modulated signal having carrier pulses spaced relative to each other to represent a variable pulse width encoded digital data signal. A detector generates a variable pulse width encoded signal in response to received carrier pulses. A decoder decodes the variable pulse width encoded signal to generate the digital data signal.

Modulation technique providing high data rate through band limited channels

A variable aperture coding/decoding system suitable for use in a spread spectrum system provides multiple phase coding of an input NRZ bitstream. Each bit of a coded output signal is coded to encompass a predetermined different number of clock periods depending on the logic level of the input signal. A coded bit exhibits a predetermined reference number of clock periods, eg., 9, when the input signal does not exhibit a logic level transition. When the input signal exhibits a phase change from a 0 to a 1 logic level, the bit width of an associated coded bit is increased by 1 clock period, to 10 clock periods. When the input signal exhibits a phase change from a 1 to a 0 logic level, the bit width of an associated coded bit is decreased by 1 clock period, to 8 clocks periods. Thus the coded output signal may contain three types of information represented by a bit width change proportional to predetermined factor N.

Growing community of inventors

Indianapolis, IN, United States of America

Zhiming Zhang