733 results about "Delta modulation" patented technology

A capacitive sensor includes a switching capacitor circuit, a comparator, and a charge dissipation circuit. The switching capacitor circuit reciprocally couples a sensing capacitor in series with a modulation capacitor during a first switching phase and discharges the sensing capacitor during a second switching phase. The comparator is coupled to compare a voltage potential on the modulation capacitor to a reference and to generate a modulation signal in response. The charge dissipation circuit is coupled to the modulation capacitor to selectively discharge the modulation capacitor in response to the modulation signal.

A power line communication device for communicating data signals over a power line is provided. One example embodiment comprises a conditioning circuit configured to be coupled to the power line and a modem communicatively coupled to the conditioning circuitry to transmit and receive data signals over the power line via the conditioning circuitry. The modem may be configured to transmit and receive orthogonal frequency division multiplexed data signals that comprise a plurality of sub-carriers, wherein the modem is adapted to vary the transmit power for each of a plurality of subsets of the plurality of sub-carriers from substantially zero power to a plurality of increments above zero power. The modem also may be adapted to transmit and receive data signals with the transmit power for each of a plurality of subsets of the plurality of sub-carriers being different and to transmit and receive using a different modulation scheme at different sub-carriers.

Introduce a pulse length control mechanism to generate virtual multi-level output pulses for a Class-D Amplifier, which has only 2 physical output levels. Typically a Sigma-Delta-Modulator converts the input signal into high frequency low bit rate. The disclosed invention adds functions to transform the SDM signal into pulses with equivalent multi-level time-voltage areas and adds a pulse-length-control mechanism to produce various output pulse patterns, where the summations of the positive and negative pulses, within one sampling period, result in time-voltage area values, corresponding to 3 or more digital levels. Thus the invention produces higher signal quality at lower sampling rates.

Method of embedding watermarks in a signal encoded by an encoder having a feedback loop, for example, a sigma-delta modulator (21,22,23). A digital watermark pattern (w) is embedded in the signal (z) by modifying selected samples (for example, replacing every 100th bit) of the encoded signal (y) by samples of the watermark pattern. The circuit (24) for modifying the samples is located inside the loop of the encoder. The effect of watermarking is thus compensated in subsequent encoding steps and the signal-to-noise ratio is only slightly affected.

A clock system includes a digital phase/frequency detector (DPFD), a buffer, a digitally-controlled oscillator (DCO) including a sigma-delta modulator (SDM), an adder, a first frequency divider. The DPFD may have a first input for a reference input clock and a second input for a feedback signal, and outputting a difference signal representing a phase and/or frequency difference between the reference input clock and the feedback signal. The buffer may be coupled to the DPFD for accumulating the difference signal over time. The sigma-delta modulator (SDM) may have a control input coupled to the buffer. The adder may have inputs coupled to the (SDM) and a source of an integer control word. The first frequency divider may have an input for a clock signal and a control input coupled to the adder, the DCO generating an output clock signal having an average frequency representing a frequency of the input clock signal divided by (N+F/M), wherein N is determined by the integer control word and F/M is determined by an output of the SDM. The system clock also may include a phase-locked loop (PLL) including a phase/frequency detector that has a first input coupled to the output of the DCO and a second input that is phase-locked to the first input, and a second frequency divider coupled from the second input of the PLL to the second input of the DPFD.

Each of plural sigma-delta modulators having a sampling capacitor, an integrator, and a quantizer are connected to each other in parallel. Each of the sigma-delta modulators conducts parallel oversampling in which an analog input signal is sampled by a sampling capacitor, and the sampling result is quantized by the integrator and the quantizer. Then, the quantized values of the sigma-delta modulators are added to obtain MSBs, the residue values of the integrators after quantizing in the respective sigma-delta modulators are added, and the addition result of the residue values is converted analog-to-digital to obtain LSBs.

An optical recording disk has audio signals recorded as data encoded in accordance with DVD specifications, both as PCM data and as single bit stream data that are generated by sigma-delta modulation, thereby providing both the improved audio reproduction capability of single bit stream data and also compatibility with existing types of DVD playback apparatus. Data are recorded using proposed new DVD stream modes, having 10 data channels, 48 kHz PCM sampling frequency and 16 or 20 bits/sample, with the ratio (2:8) of data channel capacities allocated to the PCM data and single bit stream data being made identical to the ratio of the respective bit rates at which the PCM data and single bit stream data are generated.

A method of controlling a sigma delta modulator with a loop which establishes a signal transfer function, STF, and a quantization noise transfer function, NTF, of the sigma delta modulator, wherein the sigma delta modulator receives an input signal, x(n), and provides a modulated output signal, y(n) in response to the input signal. The method is characterized in comprising the step of controlling the sigma delta modulator to change the quantization noise transfer function, NTF, in response to a signal feature, A(n), which is correlated with the input signal.

Systems, methods, and circuits provide a time to digital converter comprising a sigma-delta modulator. The sigma-delta based time to digital converter may receive an analog signal representing a phase error between a reference clock signal and a feedback clock signal and generate a digital signal representing the phase error. The sigma-delta modulator may comprise a subtractor, an integrator, a feedback path, and a quantizer. The subtractor may receive the analog signal and subtract a feedback signal from the analog signal and the integrator may integrate the output of the subtractor. The sigma-delta modulator may accumulate a voltage or a charge over a capacitor as pulses are received from the analog signal and after a number of clock cycles, the capacitor may be discharged to generate a pulse in an output signal.

A transducer amplification circuit may include a preamplifier circuit with a signal input receiving a transducer signal to provide an amplified transducer signal comprising audible frequency components and ultrasonic frequency components. The transducer amplification circuit may include a first sigma-delta modulator configured to sample and quantize the amplified transducer signal to generate a first digital transducer signal comprising a first quantization noise signal. The first sigma-delta modulator may include a first noise transfer function having a high pass response in at least a portion of an audible frequency range to push the quantization noise signal to ultrasonic frequencies. A second sigma-delta modulator is configured to sample and quantize the amplified transducer signal to generate a second digital transducer signal comprising a second quantization noise signal. The second sigma-delta modulator may include a second noise transfer function with a magnitude minimum placed at the ultrasonic frequencies.

Digital-to-analog and analog-to-digital conversion are implemented in or using programmable logic. The DAC and ADC circuits may be hardwired in a programmable logic integrated circuit or may be implemented using an intellectual property (IP) core. The IP core would be a series of bits to configure the logic cells and other programmable logic of an integrated circuit to include one or more DACs or ADC, or both on the same integrated circuit. The DAC may be a sigma-delta-modulator-based implementation or a resistor-ladder-based implementation.

A method and apparatus to receive and demodulate call related information, e.g., Caller ID information, in an audio codec placed on the line side and powered by current drawn from the telephone line. The audio codec includes a 1st order SIGMA/DELTA A/D converter to digitize the signal from the telephone line with SIGMA/DELTA modulation. The 1st order SIGMA/DELTA A/D converter may be a scaleable component capable of alternative operation in a 2nd order. The SIGMA/DELTA encoded digitized signal is digitally processed by a DSP including an amplifier module, a digital filter, a limit/slice module, and an FSK decoder to receive and output the call related information. Placement of the audio codec on the line side and the scaleable SIGMA/DELTA A/D converter provides significantly reduced power requirements for the audio codec, thus allowing operation from power derived from the telephone line. In another embodiment, to further reduce power consumption of the audio codec, the 1st order SIGMA/DELTA A/D converter is sampled at a slower rate than is conventional, e.g., by first dividing or otherwise providing a slower sampling clock.

The invention belongs to the technical field of analog IC (Integrated Circuit) design, in particular to a high-bandwidth low-power consumption frequency-compensation three-stage operational amplifier. The amplifier comprises an input stage, a second stage, an output stage, a common mode feedback stage, a comprehension circuit, an internal feedforward circuit, wherein the second stage is connectedwith the input stage, the output stage is connected with the second stage and used for amplifying a signal output by the second stage and driving an external load circuit, the common mode feedback stage extracts the common mode level of the differential output stage and stabilizes the common mode level, the comprehension circuit comprises a traditional trsanscondutance comprehension circuit, a miller comprehension circuit and a resistor for separating a high-frequency zero pole, and the internal feedforward circuit is used for comprehending an internal additional pole and forming a push-pull circuit together with the output stage to reduce static power consumption. The three-stage operational amplifier realizes high gain, high bandwidth and high stability under the condition of little DC power consumption and can be used in a high-speed analog-digital conversion circuit, such as a sigma-delta modulator suitable for the bandwidth of an LTE (Line Terminator Equipment) wireless communication protocol.

The use of a PLL including a phase detector responsive to the phase difference between an input signal and a feedback signal and which pilots an oscillator in function of this difference, is envisaged. The PLL also includes a feedback path that is responsive to the signal generated by the oscillator and which generates said feedback signal via at least one divider with a variable division ratio. The division ratio of said divider is modulated via a sigma-delta modulator, the input of which is fed with a triangular-wave modulating signal. The preferred application is that of a spread spectrum clock generator (SSCG) for digital electronic systems.

A transmitter and method is provided for digitally upconverting a baseband digital signal to a modulated intermediate frequency (IF) digital signal and sigma-delta modulating the IF digital signal. The baseband digital signal is split into N phases, as can be accomplished using a polyphase interpolation technique (polyphase filter), and modulated. The modulated N phases are not recombined and each phase is further modulated, as can be accomplished using a digital-to-digital sigma-delta modulator that generates digital output signals at the same rate. A high speed digital multiplexer multiplexes the digital output signals into a single bit stream at a higher rate for subsequent power amplification and RF transmission.

A clock system includes a digital phase/frequency detector (DPFD), a buffer, a digitally-controlled oscillator (DCO) including a sigma-delta modulator (SDM), an adder, a first frequency divider. The DPFD may have a first input for a reference input clock, a second input for a feedback signal, the DPFD generating an output representing a difference between the reference input clock and the feedback signal. The buffer may be coupled to the DPFD for accumulating the difference signal over time. The sigma-delta modulator (SDM) may have a control input coupled to the buffer. The adder may have inputs coupled to the (SDM) and a source of an integer control word. The first frequency divider may have an input for a clock signal and a control input coupled to the adder, the DCO generating an output clock signal having an average frequency representing a frequency of the input clock signal divided by (N+F/M), wherein N is determined by the integer control word and F/M is determined by an output of the SDM. The system clock also may include a second frequency divider coupled to the DCO output clock signal outputting the feedback signal to the DPFD.

A capacitive sensor includes a switching capacitor circuit, a comparator, and a charge dissipation circuit. The switching capacitor circuit reciprocally couples a sensing capacitor in series with a modulation capacitor during a first switching phase and discharges the sensing capacitor during a second switching phase. The comparator is coupled to compare a voltage potential on the modulation capacitor to a reference and to generate a modulation signal in response. The charge dissipation circuit is coupled to the modulation capacitor to selectively discharge the modulation capacitor in response to the modulation signal.

The present invention relates to a microphone assembly comprising a microphone assembly casing having a sound inlet port and a transducer for receiving acoustic waves through the sound inlet port. The transducer converts the received acoustic waves to analog audio signals. The assembly according to the present invention further comprises an electronic circuit positioned within the microphone assembly casing, said electronic circuit comprising a pre-amplifier and an analog-to-digital converter preferably in form of a sigma-delta modulator so as to convert amplified analog audio signals to digital audio signals.