A PAM-4 receiver with jitter compensation clock and data recovery is provided. The receiver includes a first-order delay-locked loop (DLL) which employs a bang-bang phase detector (BBPD) and a voltage-controlled delay line (VCDL) circuit supporting 40 MHz jitter tracking bandwidth and static phase skew elimination. A second-order wideband phase-locked loop (WBPLL) using the ¼-rate reference clock provides multi-phase clock generation with low input-to-output latency. To suppress the consequent jitter transfer, a jitter compensation circuit (JCC) acquires the jitter transfer amplitude and frequency information by detecting the DLL loop filter voltage (VLF(s)) signal, and generates an inverted loop filter voltage signal, denoted as VLF.sub.INV(s). The VLF.sub.INV(S) modulates a group of complementary VCDLs (C-VCDLs) to attenuate the jitter transfer on both recovered clock and data. With the provided receiver, a jitter compensation ratio up to 60% can be supported from DC to 4 MHz, with a −3-dB corner frequency of 40 MHz.

A power transmitter includes: a first switch coupled between a first node and a reference voltage node; a second switch configured to be coupled between a power supply and the first node; a coil and a capacitor coupled in series between the first node and the reference voltage node; a first sample-and-hold (S&H) circuit having an input coupled to the first node; and a timing control circuit configured to generate a first control signal, a second control signal, and a third control signal that have a same frequency, where the first control signal is configured to turn ON and OFF the first switch alternately, the second control signal is configured to turn ON and OFF the second switch alternately, and where the third control signal determines a sampling time of the first S&H circuit and has a first pre-determined delay from a first edge of the first control signal.

A power transmitter includes: a first switch coupled between a first node and a reference voltage node; a second switch configured to be coupled between a power supply and the first node; a coil and a capacitor coupled in series between the first node and the reference voltage node; a first sample-and-hold (S&H) circuit having an input coupled to the first node; and a timing control circuit configured to generate a first control signal, a second control signal, and a third control signal that have a same frequency, where the first control signal is configured to turn ON and OFF the first switch alternately, the second control signal is configured to turn ON and OFF the second switch alternately, and where the third control signal determines a sampling time of the first S&H circuit and has a first pre-determined delay from a first edge of the first control signal.

A method for initial timing synchronization for a WTRU to communicate with a network includes receiving an in-channel narrowband synchronization sequence from the network to enable initial coarse timing synchronization, determining coarse timing offset and a range between a beam source of a network transmitter and the WTRU, selecting a wideband sequence for fine timing synchronization using the estimated range, transmitting the selected wideband sequence for fine timing synchronization during an uplink timing occasion, receiving from the network a transmission of the selected wideband sequence for fine timing synchronization, and establishing fine timing synchronization between the WTRU and the network using the selected sequence.

Embodiments of this application disclose a wireless charging system. The wireless charging system includes a first electronic device, a wireless charging device, and a second electronic device. The wireless charging device is located between the first electronic device and the second electronic device. The wireless charging device is an auxiliary device of the first electronic device and is physically connected to the first electronic device, the wireless charging device includes a receiver circuit and a housing, the receiver circuit includes a receiver coil, and the receiver coil is located on an inner side of the housing. The first electronic device is configured to: charge the wireless charging device, charge the second electronic device through the wireless charging device, and receive power from the second electronic device through the wireless charging device.

Messages are transmitted in closely-spaced subcarriers in 5G and 6G, configured so that each subcarrier signal is orthogonal to the adjacent subcarrier signals. However, many effects can penetrate that orthogonality—distortion, interference, frequency variations, amplitude variations, crosstalk, etc.—collectively termed energy spill-over. To combat this problem, a receiver can determine the total energy spill-over into adjacent subcarriers by measuring a residual signal in a subcarrier with no transmission, adjacent to another subcarrier with a known transmission. The receiver can measure the amplitude, phase, temporal or spectral properties, and so forth of the residual signal. The receiver can then correct the message during signal processing, by calculating a function of the residual signal and subtracting it from each digitized subcarrier signal of a message. This can largely restore the inter-subcarrier orthogonality, improving messaging reliability while avoiding message faults and costly retransmissions.

Messages are transmitted in closely-spaced subcarriers in 5G and 6G, configured so that each subcarrier signal is orthogonal to the adjacent subcarrier signals. However, many effects can penetrate that orthogonality—distortion, interference, frequency variations, amplitude variations, crosstalk, etc.—collectively termed energy spill-over. To combat this problem, a receiver can determine the total energy spill-over into adjacent subcarriers by measuring a residual signal in a subcarrier with no transmission, adjacent to another subcarrier with a known transmission. The receiver can measure the amplitude, phase, temporal or spectral properties, and so forth of the residual signal. The receiver can then correct the message during signal processing, by calculating a function of the residual signal and subtracting it from each digitized subcarrier signal of a message. This can largely restore the inter-subcarrier orthogonality, improving messaging reliability while avoiding message faults and costly retransmissions.

A power transmitter includes: a first switch coupled between a first node and a reference voltage node; a second switch configured to be coupled between a power supply and the first node; a coil and a capacitor coupled in series between the first node and the reference voltage node; a first sample-and-hold (S&H) circuit having an input coupled to the first node; and a timing control circuit configured to generate a first control signal, a second control signal, and a third control signal that have a same frequency, where the first control signal is configured to turn ON and OFF the first switch alternately, the second control signal is configured to turn ON and OFF the second switch alternately, and where the third control signal determines a sampling time of the first S&H circuit and has a first pre-determined delay from a first edge of the first control signal.

A power transmitter includes: a first switch coupled between a first node and a reference voltage node; a second switch configured to be coupled between a power supply and the first node; a coil and a capacitor coupled in series between the first node and the reference voltage node; a first sample-and-hold (S&H) circuit having an input coupled to the first node; and a timing control circuit configured to generate a first control signal, a second control signal, and a third control signal that have a same frequency, where the first control signal is configured to turn ON and OFF the first switch alternately, the second control signal is configured to turn ON and OFF the second switch alternately, and where the third control signal determines a sampling time of the first S&H circuit and has a first pre-determined delay from a first edge of the first control signal.

An example apparatus includes: a receiver operable to receive a modulated input signal at a receiver input and output a demodulated signal at a receiver output, the receiver comprising a switch having a first current terminal and a first control terminal, the first current terminal coupled to the receiver output. The example apparatus includes a capacitor having a first terminal and a second terminal, the second terminal coupled to the first control terminal and the first terminal coupled to the receiver input. The example apparatus includes a resistor having a third terminal and a fourth terminal, the fourth terminal coupled to the first control terminal. The example apparatus includes a voltage offset source having an input and an output, the output coupled to the third terminal. The example apparatus includes a current source coupled to the first current terminal.