An optical line terminal (OLT) in flexible passive optical network (PON) transmits a downstream signal with two or more modulation formats, wherein at least one of the modulation formats is a modified PAMx modulation format and wherein x is greater than 2. The modified PAMx modulation encodes data bits such that the probability of at least one predetermined transition between amplitude levels is modified. Furthermore, an optical network unit (ONU) in the flexible PON is assigned to one of the plurality of modulation formats based on one or more parameters, such as configuration of the ONU and line conditions.

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 is 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 is coupled to a signal path for the feedback signal to provide a passive filter.

A method of operating a memory device includes receiving a training request for a data channel, detecting at least one mode parameter according to the training request, transmitting the detected mode parameter to an external device, setting at least one of an NRZ mode and a PAM4 mode to a transmission signaling mode based on mode register set setting information from the external device, and performing communications with the external device according to the set transmission signaling mode.

Various embodiments include a computing device memory system having a memory device, a memory physical layer communicatively connected to the memory device, a first input/output (IO) voltage supply electrically connected to the memory device and to the memory physical layer, and a second TO voltage supply electrically connected to the memory device and to the memory physical layer, in which the memory device and the physical layer are configured to communicate data of a memory transaction using a 3 level pulse amplitude modulation (PAM) IO scheme.

Various embodiments include a computing device memory system having a memory device, a memory physical layer communicatively connected to the memory device, a first input/output (IO) voltage supply electrically connected to the memory device and to the memory physical layer, and a second TO voltage supply electrically connected to the memory device and to the memory physical layer, in which the memory device and the physical layer are configured to communicate data of a memory transaction using a 3 level pulse amplitude modulation (PAM) IO scheme.

Various embodiments include a computing device memory system having a memory device, a memory physical layer communicatively connected to the memory device, a first input/output (IO) voltage supply electrically connected to the memory device and to the memory physical layer, and a second IO voltage supply electrically connected to the memory device and to the memory physical layer, in which the memory device and the physical layer are configured to communicate data of a memory transaction using a 3 level pulse amplitude modulation (PAM) IO scheme.

Various embodiments include a computing device memory system having a memory device, a memory physical layer communicatively connected to the memory device, a first input/output (IO) voltage supply electrically connected to the memory device and to the memory physical layer, and a second IO voltage supply electrically connected to the memory device and to the memory physical layer, in which the memory device and the physical layer are configured to communicate data of a memory transaction using a 3 level pulse amplitude modulation (PAM) IO scheme.

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.

A method of operating a memory device includes receiving a training request for a data channel, detecting at least one mode parameter according to the training request, transmitting the detected mode parameter to an external device, setting at least one of an NRZ mode and a PAM4 mode to a transmission signaling mode based on mode register set setting information from the external device, and performing communications with the external device according to the set transmission signaling mode.