17 results about "Pulse-amplitude modulation" patented technology

Provided are a wired transmission time division duplex system and a node device thereof. The node device comprises a receiver configured to receive a data frame; a transmitter configured to send a processed data frame; a frame header detection circuit configured to identify a frame header and a preamble in a non-return-to-zero coding format from the data frame based on a specific code sequence, and obtain frame header information accordingly, and detect a level jump edge in the frame header and the preamble, and output a reference clock signal based on the detection result; and a clock and data recovery circuit configured to map a multi-level digital signal of a data segment after the frame header and the preamble into binary data bits using a corresponding pulse amplitude modulation format based on the frame header information, and recover a local receiving clock based on the reference clock signal. The slave node device effectively overcomes the synchronization difficulty and slow clock recovery in a multi-level pulse amplitude modulation system.

A system and method for distortion reduction. In some embodiments, a system for distortion reduction includes a transmitter comprising pulse amplitude modulation driver circuitry. The pulse amplitude modulation driver circuitry may include a main driver comprising a most significant bit (MSB) amplifier and a least significant bit (LSB) amplifier. The LSB amplifiers may include an upper arm and a lower arm, the strength of which is adjustable.

Described apparatuses and methods are directed to equalization with pulse-amplitude modulation (PAM) signaling. As bus frequencies have increased, the time for correctly transitioning between voltage levels has decreased, which can lead to errors. Symbol decoding reliability can be improved with equalization, like with decision-feedback equalization (DFE). DFE, however, can be expensive for chip area and power usage. Therefore, instead of applying DFE to all voltage level determination paths in a receiver, DFE can be applied to a subset of such determination paths. With PAM4 signaling, for example, a DFE circuit can be coupled between an output and an input of a middle slicer. In some cases, symbol detection reliability can be maintained even with fewer DFE circuits by compressing a middle eye of the PAM4 signal. The other two eyes thus have additional headroom for expansion. Encoding schemes, impedance terminations, or reference voltage levels can be tailored accordingly.

Reduced complexity maximum likelihood sequence detectors (rMLSDs) for detecting multi-bit symbols, such as symbols found in pulse amplitude modulation (PAM), quadrature amplitude modulation (QAM), and phase shift keying (PSK) signal constellations with more than two constellation points, are disclosed. One illustrative digital communication receiver includes an initial equalizer that derives an initial sequence of symbol decisions from a filtered received signal, each symbol decision in the initial sequence having a second possible symbol decision, and an rMLSD that derives a final sequence of symbol decisions by evaluating a state metric for only each symbol decision in the initial sequence and its second possible symbol decision.

This invention discloses a display module, its data voltage adjustment method, and a display device. The display module includes a pixel circuit, a light-emitting element, a first chip, and a second chip. The pixel circuit includes a pulse amplitude modulation module and a pulse width modulation module. The pulse amplitude modulation module includes a first data writing unit, the input terminal of which is electrically connected to the first chip, and the first chip provides a data voltage to the first data writing unit. The pulse width modulation module includes a second data writing unit, the input terminal of which is electrically connected to the second chip, and the second chip provides a data voltage to the second data writing unit. This invention achieves flexible control of the light-emitting current and light-emitting duration of the light-emitting element by providing an adjustable data voltage to the pulse amplitude modulation module through the first chip and the second chip, thereby improving the display effect of different gray levels.

A system and method for distortion mitigation. In some embodiments, a system, includes: a transmitter, including: a pulse amplitude modulation driver circuit. The pulse amplitude modulation driver circuit may include a main driver including a most significant bit (MSB) amplifier, and a least significant bit (LSB) amplifier. The LSB amplifier may include an upper arm and a lower arm, a strength of the upper arm or a strength of the lower arm being adjustable.

The application discloses a rate calibration method of a pulse amplitude modulation signal and a computer storage medium, and belongs to the technical field of communication signal processing. The method comprises the following steps: performing edge detection on the pulse amplitude modulation signal according to all voltage judgment thresholds of the pulse amplitude modulation signal, and determining four groups of edge characteristic data; determining a histogram according to the four groups of edge characteristic data; determining the interval range center value corresponding to an initial rate as an initial search center, and determining a first characteristic peak value and a second characteristic peak value according to the initial search center; determining a termination boundary of a target characteristic region according to the number of edge widths contained between the center values of the two characteristic peak values; determining a starting boundary according to the termination boundary and the interval range center value of the first characteristic peak value; determining a median point of the target characteristic region as a target center value; determining a sampling point estimation value according to the target center value and a single symbol period; and determining a final rate of the pulse amplitude modulation signal according to the sampling point estimation value and a sampling rate.

This application discloses a quantum sensing-based lidar gas telemetry system and method. The system includes a DFB laser, a laser temperature control module, a laser current drive module, an acousto-optic modulator, a coaxial optical path for transmission and reception, an SPD single-photon detector, an amplifier circuit module, and an MCU. The temperature control module modulates the wavelength of the DFB laser, the current drive module modulates the power, and the acousto-optic modulator modulates the pulse amplitude, giving the output laser triple modulation characteristics of wavelength scanning modulation, current-gated modulation, and pulse amplitude modulation at different time scales. The modulated laser is emitted into the target space and the diffuse reflection echo is received, where the SPD single-photon detector counts single photons. The MCU performs time counting based on the counting signal to determine the target distance and performs absorption demodulation during wavelength scanning. Based on Beer-Lambert's law, the gas path integral concentration is inverted to achieve synchronous measurement of gas concentration and target distance.

The present disclosure relates to generating optical PAM-4 signals in Mach-Zehnder modulators. Embodiments are disclosed for generating an optical pulse amplitude modulation 4-level (PAM-4) signal from a bandwidth-limited duobinary electrical signal in a Mach-Zehnder modulator. An example system includes an MZM structure including a first waveguide interferometer arm structure associated with a first semiconductor device and a second waveguide interferometer arm structure associated with a second semiconductor device. A multi-binary electrical signal is applied to the first semiconductor device and the second semiconductor device or between the first semiconductor device and the second semiconductor device to convert an input optical signal provided to the MZM structure to an optical PAM-4 signal.

A pixel circuit includes a light-emitting diode (LED), a first driving transistor, a second driving transistor, a pulse amplitude modulation circuit, and a pulse width modulation circuit. The first driving transistor has a first terminal, a control terminal receiving an amplitude control signal, and a second terminal. The second driving transistor has a first terminal coupled to the second terminal of the first driving transistor, a control terminal receiving a width control signal, and a second terminal coupled to an anode of the LED. A channel polarity of the second driving transistor is different from that of the first driving transistor. The pulse amplitude modulation circuit provides the amplitude control signal based on an emission signal and an amplitude data voltage. The pulse width modulation circuit provides the width control signal based on the emission signal, a swing signal, and a width data voltage.

Various embodiments of the present disclosure are directed towards an optical module comprising an optical modulator device (OMD) for pulse amplitude modulation (PAM) in which the OMD comprises multiple modulator segments. A first modulator segment and a second modulator segment are spaced from each other along a ring-shaped waveguide. Further, a length of the second modulator segment is twice a length of the first modulator segment. As such, a power factor of the second modulator segment is twice a power factor of the first modulator segment. During use of the OMD, the first and second modulator segments are driven by separate non-return-to-zero (NRZ) electrical signals. The NRZ electrical signals are generated by a driver, which generates the NRZ electrical signals so as to coordinate operation of the first and second modulator segments to generate a PAM optical signal.

A display device is provided. The display device may comprise: a display panel including a pixel array in which pixels having a plurality of inorganic light-emitting elements are arranged in a plurality of row lines, and sub-pixel circuits corresponding to the inorganic light-emitting elements of the pixel array; and a driving unit for driving the sub-pixel circuits. Each of the sub-pixel circuits can include: a pulse amplitude modulation (PAM) circuit which includes a driving transistor, and which drives the driving transistor so as to provide a driving current to a corresponding inorganic light-emitting element on the basis of an image data voltage; and a first transistor having a gate terminal connected to a gate terminal of the driving transistor and having a drain terminal connected to a source terminal of the driving transistor.

This application provides a pixel driving circuit and its driving method, as well as a display panel. The circuit includes a light-emitting module, a pulse amplitude modulation module, and a pulse width modulation module. The pulse amplitude modulation module includes a driving transistor, one end of which is connected to the light-emitting module. The pulse width modulation module is connected to the pulse amplitude modulation module and includes a fourth transistor. The gate of the fourth transistor is used to receive an input driving signal during the light-emitting phase of each frame driving cycle. The pulse width modulation module controls the light-emitting duration of the light-emitting module according to the driving signal via the driving transistor. The voltage value of the driving signal increases in a stepwise manner until the fourth transistor turns on. This application improves the uniformity of panel light emission and the stability of the driving architecture.

This application provides a display device and its driving method. The display device includes a display panel. The display panel includes a plurality of pixel units. Each pixel unit includes a first sub-pixel and at least one second sub-pixel. The first sub-pixel includes a first driving circuit and a first light-emitting diode. The first driving circuit includes a first pulse amplitude modulation control module, a first transistor, and a second transistor. The second sub-pixel includes a second driving circuit and a second light-emitting diode. The second driving circuit includes a second pulse amplitude modulation control module, a second pulse width modulation control module, a third transistor, and a fourth transistor. The technical solution of this application reduces the number of data signal lines, lowers the complexity of the driving circuit, improves color point stability and brightness uniformity, reduces transient current peaks, and improves the reliability of the display device.