A data communication method in which input digital data is received and encoded into an encoded waveform having zero crossings representative of the input digital data. The encoding includes generating the encoded waveform based upon a continuous piecewise function having sinusoidal components. The continuous piecewise function may be used in generating a plurality of symbol waveforms, each of which occupies a period of the encoded waveform and represents bits of the input digital data. The plurality of symbol waveforms are defined so that a value of a phase offset used in the continuous piecewise function is different for each of the plurality of symbol waveforms, thereby resulting in each symbol waveform having a different zero crossing. An encoded analog waveform is generated from a representation of the encoded waveform and transmitted to a receiver.

An equalizing transmitter coupled to a serial transmission line has a driver circuit coupled between an input signal and the serial transmission line, the driver circuit being configured to receive power at a first voltage level. The equalizing transmitter has one or more helper circuits, each helper circuit being configured to receive a control signal and to pull the serial transmission line to a second voltage level when a pulse is present in the control signal. The second voltage level may be greater than the first voltage level. The equalizing transmitter has one or more pulse generation circuits, each pulse generation circuit being configured to receive the input signal and a delayed version of the input signal and to provide the pulse in the control signal when a difference in voltage state is detected between the input signal and the delayed version of the input signal.

A method of recovering information encoded by a modulated sinusoidal waveform having first, second, third and fourth data notches at respective phase angles, where a power of the modulated sinusoidal waveform is reduced relative to a power of an unmodulated sinusoidal waveform within selected ones of the first, second, third and fourth data notches so as to encode input digital data. The method includes receiving the modulated sinusoidal waveform and generating digital values representing the modulated sinusoidal waveform. A digital representation of the unmodulated sinusoidal waveform is subtracted from the digital values in order to generate a received digital data sequence, which includes digital data notch values representative of the amplitude of the modulated sinusoidal waveform within the first, second, third and fourth data notches. The input digital data is then estimated based upon the digital data notch values.

A receiver includes an equalization circuit configured to output a data sample signal and an edge sample signal by sampling a data input signal according to clock signal, and to perform an equalization operation according to the data sample signal and the edge sample signal; and a clock gate circuit configured to select the clock signals from among a plurality of multi-phase clock signals according to a selection signal.

Differential-signal receivers. One example is a method of operating a differential-signal receiver, the method comprising: receiving a first differential signal on a differential-signal pair, the first differential signal accompanying a common-mode voltage that is positive relative to a reference voltage of the differential-signal receiver; clamping, when the first differential signal is positive, an OUT+ node at a first voltage; and clamping, when the first differential signal is negative, the OUT- node at a second voltage.

Differential-signal receivers. One example is a method of operating a differential-signal receiver, the method comprising: receiving a first differential signal on a differential-signal pair, the first differential signal accompanying a common-mode voltage that is positive relative to a reference voltage of the differential-signal receiver; clamping, when the first differential signal is positive, an OUT+ node at a first voltage; and clamping, when the first differential signal is negative, the OUT− node at a second voltage.

An equalizing transmitter coupled to a serial transmission line has a driver circuit coupled between an input signal and the serial transmission line, the driver circuit being configured to receive power at a first voltage level. The equalizing transmitter has one or more helper circuits, each helper circuit being configured to receive a control signal and to pull the serial transmission line to a second voltage level when a pulse is present in the control signal. The second voltage level may be greater than the first voltage level. The equalizing transmitter has one or more pulse generation circuits, each pulse generation circuit being configured to receive the input signal and a delayed version of the input signal and to provide the pulse in the control signal when a difference in voltage state is detected between the input signal and the delayed version of the input signal.

A method for identifying electronic device is applied to a terminal device and includes: sending, in response to receiving a power-on signal of the electronic device, a detection signal to the electronic device; acquiring waveform information of the detection signal; and determining a type of the electronic device according to the waveform information.

Methods and apparatus are disclosed for communicating multiple logic states across a digital isolator. The digital isolator is a universal serial bus (USB) isolator in some embodiments. The digital isolator includes one or more single-bit data channels. Three or more logic states of information are transmitted across the single-bit data channel(s). The logic states are distinguished by a pulse sequence, and in particular a number of edges of the pulse sequence and a final value or final edge of the pulse sequence.

A receiver includes an equalization circuit configured to output a data sample signal and an edge sample signal by sampling a data input signal according to clock signal, and to perform an equalization operation according to the data sample signal and the edge sample signal; and a clock gate circuit configured to select the clock signals from among a plurality of multi-phase clock signals according to a selection signal.