The guard-space reference disclosed herein is a signal transmitted in the guard spaces separating message data intervals, and configured to reveal amplitude noise or phase noise or both, using 5G or 6G technology. For example, the transmitter can transmit an I-branch with a predetermined amplitude level, and an orthogonal Q branch with zero amplitude, in the guard space. The receiver can measure the received amplitude and phase of the guard-space reference, subtract the initial amplitude and phase, and thereby measure both phase noise and amplitude noise. The receiver can then subtract the measured amplitude and phase effects from the message data, thereby negating both phase noise and amplitude noise. Guard-space references disclosed herein can preserve the inter-subcarrier orthogonality, inter-symbol separation, and signal circularity advantages of prior art, while additionally providing both amplitude noise and phase noise mitigation. Examples are suitable for wireless standards.

The guard-space reference disclosed herein is a signal transmitted in the guard spaces separating message data intervals, and configured to reveal amplitude noise or phase noise or both, using 5G or 6G technology. For example, the transmitter can transmit an I-branch with a predetermined amplitude level, and an orthogonal Q branch with zero amplitude, in the guard space. The receiver can measure the received amplitude and phase of the guard-space reference, subtract the initial amplitude and phase, and thereby measure both phase noise and amplitude noise. The receiver can then subtract the measured amplitude and phase effects from the message data, thereby negating both phase noise and amplitude noise. Guard-space references disclosed herein can preserve the inter-subcarrier orthogonality, inter-symbol separation, and signal circularity advantages of prior art, while additionally providing both amplitude noise and phase noise mitigation. Examples are suitable for wireless standards.

Various embodiments relate to an amplitude shift keying (ASK) demodulator for demodulating an input signal, including: a frequency filter configured to receive the input signal, wherein the frequency filter includes adjustable components configured to adjust the frequency response of the frequency filter; a rectifier configured to rectify an output of the frequency filter, wherein the rectifier includes an adjustable current source configured to adjust the current consumption of the rectifier; a reference signal generator configured to produce a reference signal; a current to voltage converter configured to convert the current of the rectified signal to a rectified voltage and to convert the current of the reference signal to a reference voltage; and a comparator configured to compare the rectified voltage to the reference voltage and to produce a demodulated output signal.

Apparatuses, systems, and methods for high-pass filtering pre-emphasis circuits. A device may use a pre-emphasis driver to provide a multi-level signal based on multiple binary signals. The pre-emphasis driver includes a primary driver coupled in parallel with at least one equalizer path, each of which includes an equalizer driver and a filtering element. The filtering element may be an AC filtering element, such as a capacitor. The equalizer paths may contribute equalized signal(s) which have a high-pass filtering behavior. The pre-emphasis circuit may combine the primary signal from the primary driver and the equalized signals to generate an overall output multi-level signal. In some embodiments, the pre-emphasis driver may be a pulse amplitude modulated (PAM) driver, such as a PAM4 driver with four levels of the multi-level driver.

Apparatuses, systems, and methods for high-pass filtering pre-emphasis circuits. A device may use a pre-emphasis driver to provide a multi-level signal based on multiple binary signals. The pre-emphasis driver includes a primary driver coupled in parallel with at least one equalizer path, each of which includes an equalizer driver and a filtering element. The filtering element may be an AC filtering element, such as a capacitor. The equalizer paths may contribute equalized signal(s) which have a high-pass filtering behavior. The pre-emphasis circuit may combine the primary signal from the primary driver and the equalized signals to generate an overall output multi-level signal. In some embodiments, the pre-emphasis driver may be a pulse amplitude modulated (PAM) driver, such as a PAM4 driver with four levels of the multi-level driver.

Various aspects of the disclosure relate to limits for modulation and coding scheme (MCS) values. For example, a first set of limits (e.g., minimum and maximum limits) may be used for a first MCS table and a second set of limits may be used for a second MCS table. The disclosure also relates in some aspects to inter-device signaling that indicates which minimum and maximum limits for an MCS table are to be used for communication between the devices.

Various aspects of the disclosure relate to limits for modulation and coding scheme (MCS) values. For example, a first set of limits (e.g., minimum and maximum limits) may be used for a first MCS table and a second set of limits may be used for a second MCS table. The disclosure also relates in some aspects to inter-device signaling that indicates which minimum and maximum limits for an MCS table are to be used for communication between the devices.

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 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 signal transmitter circuit includes an output driver circuit configured to transmit a signal using a multi-level pulse amplitude modulation (PAM) scheme comprising a plurality of discreet signal levels. During operation, the output driver initiates a first transition of the signal to a first level of the multi-level PAM scheme from a second level of the multi-level PAM scheme, and initiates a second transition of the signal to the first level from a third level of the multi-level PAM scheme. The signal transmitter further includes a control circuit configured to control a slew rate of the signal transmitter circuit to cause the signal to reach a threshold voltage level at a first time, the first time occurring a first duration of time after the first transition is initiated, and to cause the signal to reach the threshold voltage level at a second time, the second time occurring the first duration of time after the second transition is initiated.