A PDM (pulse density modulation) signal energy detection circuit includes a digital-to-analog converter circuit for receiving a PDM digital input signal and producing an analog output signal based on the PDM digital input signal. The PDM signal energy detection circuit also includes a comparator circuit for receiving the analog output signal from the digital-to-analog converter circuit and producing a pulsed signal when a magnitude of the analog output signal exceeds a pre-set threshold. The PDM signal energy detection circuit also has a counter circuit for receiving the pulsed signal from the comparator circuit and producing an energy detection signal when a number of consecutive pulsed signals exceed a pre-set count.

A method in a transmitter circuit of generating a signal comprising a first sequence of OFDM symbols, which are to be transmitted within a frequency sub band of a second sequence of OFDM symbols is disclosed. A first cyclic prefix (CP) of the second sequence of OFDM symbols has a first duration, and a second CP of the second sequence of OFDM symbols has a second duration. In order to generate both the first and the second cyclic prefix with an integer number of equidistant samples, a first sampling rate is required. The method comprises generating the signal comprising the first sequence of OFDM symbols at a second sampling rate, lower than the first sampling rate, and adjusting a sampling phase during CPs.

A pre-driver circuit includes a differential input circuit to receive a differential-input voltage. A latch circuit can latch voltage levels of output-voltage signals at a differential output port of the pre-driver circuit. A pair of capacitors couple the differential input circuit to the latch circuit. The pre-driver circuit can enable peaking of the output-voltage signals for high-speed operation of the pre-driver circuit and a digital-to-analog converter (DAC)-driver circuit coupled to the pre-driver circuit.

A pre-driver circuit includes a differential input circuit to receive a differential-input voltage. A latch circuit can latch voltage levels of output-voltage signals at a differential output port of the pre-driver circuit. A pair of capacitors couple the differential input circuit to the latch circuit. The pre-driver circuit can enable peaking of the output-voltage signals for high-speed operation of the pre-driver circuit and a digital-to-analog converter (DAC)-driver circuit coupled to the pre-driver circuit.

A system comprises an input shuffling circuit and digital-to-analog conversion circuitry. The input shuffling circuit comprises a data input, a data output, and a control input. The input shuffling circuit is operable to receive, via the data input, an N-bit binary value, where N is an integer. The input shuffling circuit is operable to route each of the N bits of the N-bit binary word to one or more of M bits of the data output to generate an M-bit value, where M=2.sup.N, and the routing is based on a control value applied to the control input. The input shuffling circuit can be configured either in a dynamic element matching (DEM) mode or a regular binary to thermometer mode. The digital-to-analog conversion circuitry is operable to convert the M-bit value to a corresponding analog voltage and/or current. M different values of the control value may result in M different routings of the N bits of the binary word.

A system comprises an input shuffling circuit and digital-to-analog conversion circuitry. The input shuffling circuit comprises a data input, a data output, and a control input. The input shuffling circuit is operable to receive, via the data input, an N-bit binary value, where N is an integer. The input shuffling circuit is operable to route each of the N bits of the N-bit binary word to one or more of M bits of the data output to generate an M-bit value, where M=2.sup.N, and the routing is based on a control value applied to the control input. The input shuffling circuit can be configured either in a dynamic element matching (DEM) mode or a regular binary to thermometer mode. The digital-to-analog conversion circuitry is operable to convert the M-bit value to a corresponding analog voltage and/or current. M different values of the control value may result in M different routings of the N bits of the binary word.

A dynamic element matching system including sequential register groups, decode circuitry, and pointer control circuitry. Each register group includes at least two registers. The decode circuitry controls a state of each register group based on a level of a digital input signal, a relative position with respect to a begin pointer and an end pointer, and a corresponding one of multiple pseudo random probability values. The pointer control circuitry cyclically advances the end pointer among the register groups causing decode circuitry to add one or more register groups and enable a register within each added register group in response to the level of the digital input signal increasing, and also cyclically advances the begin pointer among the register groups causing the decode circuitry to remove one or more register groups and disable a register within each removed register group in response to the level of the digital input signal decreasing.

A system includes a plurality of digital-to-analog converter (DAC) channels. Each DAC channel includes a current control circuit which receives a start limit signal or an end limit signal. The current control circuit reduces an output current limit of the channel responsive to the start limit signal and increases the output current limit responsive to the end limit signal. Each channel includes a current sensor circuit adapted to measure the output current of the channel and provide a channel over-current alert signal if the output current rises above a high current limit. The system includes a controller which asserts the start limit signal if the number of channels exceeding the high current limit is greater than a maximum allowable number and asserts the end limit signal if the number of channels exceeding the high current limit is less than the maximum allowable number minus a hysteresis value.

An analog signal generating source comprising two or more digital-to-analog converters (DAC) combined to generate one or more frequency components. The analog signal source comprises a first path for generating substantially low frequency signals, the first path comprising a first one of the DACs; and a second path for generating substantially high frequency signals, the second path comprising a second one of the DACs. The analog signal source also comprises a data processor for processing an input signal and providing the processed input signal to the first and second paths; a combining circuit configured to combine outputs of the first and second paths into the source signal; a feedback portion configured to sense the source signal; and a servo loop configured to use the sensed source signal to adjust as need to maintain the source signal to substantially agree with the input signal.

Technologies for low jitter and low power ring oscillators with multi-phase signal reassembly are described. A ring oscillator circuit includes a ring oscillator with a set of M delay stages, each stage outputs a phase signal, where M is a positive integer greater than one. The ring oscillator circuit includes a phase selector circuit coupled to the ring oscillator. The phase selector circuit can receive M phase signals from the ring oscillator and generate N phase signals based on the M phase signals, where N is a positive integer less than M.