The present invention is directed to data communication. More specifically, embodiments of the present invention provide a transceiver that processes an incoming data stream and generates a recovered clock signal based on the incoming data stream. The transceiver includes a voltage gain amplifier that also performs equalization and provides a driving signal to track and hold circuits that hold the incoming data stream, which is stored by shift and holder buffer circuits. Analog to digital conversion is then performed on the buffer data by a plurality of ADC circuits. Various DSP functions are then performed over the converted data. The converted data are then encoded and transmitted in a PAM format. There are other embodiments as well.

A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.

A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.

A digital pulse width modulation driver system and method can include: receiving input digital data with a digital signal processing chip on a device; converting the input digital data into pulse width modulated data; generating an amplitude signal with the digital signal processing chip; transmitting the amplitude signal and the pulse width modulated data from a transmit interface within the device to a receive interface within an analog driver chip; and amplifying the pulse width modulated data with a driver coupled to a high voltage rail based on the amplitude signal corresponding to the high voltage rail, or amplifying the pulse width modulated data with the driver coupled to a low voltage rail based on the amplitude signal corresponding to the low voltage rail.

A digital pulse width modulation driver system and method can include: receiving input digital data with a digital signal processing chip on a device; converting the input digital data into pulse width modulated data; generating an amplitude signal with the digital signal processing chip; transmitting the amplitude signal and the pulse width modulated data from a transmit interface within the device to a receive interface within an analog driver chip; and amplifying the pulse width modulated data with a driver coupled to a high voltage rail based on the amplitude signal corresponding to the high voltage rail, or amplifying the pulse width modulated data with the driver coupled to a low voltage rail based on the amplitude signal corresponding to the low voltage rail.

A system for transmitting data over an optical communication path is configured to receive data to be encoded in a bitstream for transmission using an optical communication path and encodes the received data to obtain a bitstream. The system is further configured to determine that the bitstream includes a sequence of consecutive bits, and obtain a power level at which to transmit a portion of the bitstream based on a count of the consecutive bits in the sequence. The system may be configured to selectively activate a light source at a power level according to a modulation scheme to optically transmit the portion of the bitstream at the power level.

A system for transmitting data over an optical communication path is configured to receive data to be encoded in a bitstream for transmission using an optical communication path and encodes the received data to obtain a bitstream. The system is further configured to determine that the bitstream includes a sequence of consecutive bits, and obtain a power level at which to transmit a portion of the bitstream based on a count of the consecutive bits in the sequence. The system may be configured to selectively activate a light source at a power level according to a modulation scheme to optically transmit the portion of the bitstream at the power level.

A driver circuit of a PAM-N transmitting device transmits a PAM-N signal via a communication channel, wherein N is greater than 2, and the PAM-N signal has N signal levels corresponding to N symbols. A PAM-N receiving device receives the PAM-N signal. The PAM-N receiving device generates distortion information indicative of a level of distortion corresponding to inequalities in voltage differences between the N signal levels. The PAM-N receiving device transmits to the PAM-N transmitting device the distortion information indicative of the level of the distortion. The PAM-N transmitting device receives the distortion information. The PAM-N transmitting device adjusts one or more drive strength parameters of the driver circuit of the PAM-N transmitting device based on the distortion information.

This application relates to time-encoding modulators (TEMs). A TEM receives an input signal (S.sub.IN) and outputs a time-encoded output signal (S.sub.OUT). A filter arrangement receives the input signal and also a feedback signal (S.sub.FB) from the TEM output, and generates a filtered signal (S.sub.FIL) based, at least in part, on the feedback signal. A comparator receives the filtered signal and outputs a time-encoded signal (S.sub.PWM) based at least in part on the filtered signal. The time encoding modulator is operable in a first mode with the filter arrangement configured as an active filter and in a second mode with the filter arrangement configured as a passive filter. The filter arrangement may include an op-amp, capacitance and switch network. In the first mode the op-amp is enabled, and coupled with the capacitance to provide the active filter. In the second mode the op-amp is disabled and the capacitance coupled to a signal path for the feedback signal to provide a passive filter.

This application relates to time-encoding modulators (TEMs). A TEM receives an input signal (S.sub.IN) and outputs a time-encoded output signal (S.sub.OUT). A filter arrangement receives the input signal and also a feedback signal (S.sub.FB) from the TEM output, and generates a filtered signal (S.sub.FIL) based, at least in part, on the feedback signal. A comparator receives the filtered signal and outputs a time-encoded signal (S.sub.PWM) based at least in part on the filtered signal. The time encoding modulator is operable in a first mode with the filter arrangement configured as an active filter and in a second mode with the filter arrangement configured as a passive filter. The filter arrangement may include an op-amp, capacitance and switch network. In the first mode the op-amp is enabled, and coupled with the capacitance to provide the active filter. In the second mode the op-amp is disabled and the capacitance coupled to a signal path for the feedback signal to provide a passive filter.