The present disclosure discloses a communication apparatus including a receiver circuit and a transmitter circuit having a signal processing circuit and a DAC circuit having a primary conversion circuit and a first hybrid conversion circuit. The primary conversion circuit converts and transmits a transmission signal from the signal processing circuit to a signal transmission path. The first hybrid conversion circuit converts the transmission signal to a first receiver resistor to generate a voltage drop. The receiver circuit receives a first actual receiving signal through the signal transmission path and the first receiver resistor. The primary conversion circuit operates according to a first current including a first and a second part currents and the first hybrid conversion circuit operates according to a second current. The first part current does not change according to a resistive change. The second part current and the second current change according to the resistive change.

The present disclosure discloses a communication apparatus including a receiver circuit and a transmitter circuit having a signal processing circuit and a DAC circuit having a primary conversion circuit and a first hybrid conversion circuit. The primary conversion circuit converts and transmits a transmission signal from the signal processing circuit to a signal transmission path. The first hybrid conversion circuit converts the transmission signal to a first receiver resistor to generate a voltage drop. The receiver circuit receives a first actual receiving signal through the signal transmission path and the first receiver resistor. The primary conversion circuit operates according to a first current including a first and a second part currents and the first hybrid conversion circuit operates according to a second current. The first part current does not change according to a resistive change. The second part current and the second current change according to the resistive change.

A device and method of operation for digital compensation of dynamic distortion. The transmitter device includes at least a digital-to-analog converter (DAC) connected to a lookup table (LUT), a first shift register, and a second shift register. The method includes iteratively adjusting the input values via the LUT to induce changes in the DAC output that compensate for dynamic distortion, which depends on precursors, current cursors, and postcursors. More specifically, the method includes producing and capturing average output values for each possible sequence of three symbols using the shift register and LUT configuration. Then, the LUT is updated with estimated values to induce desired output values that are adjusted to eliminate clipping. These steps are performed iteratively until one or more check conditions are satisfied. This method can also be combined with techniques such as equalization, eye modulation, and amplitude scaling to introduce desirable output signal characteristics.

A device and method of operation for digital compensation of dynamic distortion. The transmitter device includes at least a digital-to-analog converter (DAC) connected to a lookup table (LUT), a first shift register, and a second shift register. The method includes iteratively adjusting the input values via the LUT to induce changes in the DAC output that compensate for dynamic distortion, which depends on precursors, current cursors, and postcursors. More specifically, the method includes producing and capturing average output values for each possible sequence of three symbols using the shift register and LUT configuration. Then, the LUT is updated with estimated values to induce desired output values that are adjusted to eliminate clipping. These steps are performed iteratively until one or more check conditions are satisfied. This method can also be combined with techniques such as equalization, eye modulation, and amplitude scaling to introduce desirable output signal characteristics.

Provided is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals to be transmitted over the same frequency bandwidth at the same time, including the steps of selecting a matrix F[i] from among N matrices, which define precoding performed on the plurality of baseband signals, while switching between the N matrices, i being an integer from 0 to N−1, and N being an integer at least two, generating a first precoded signal z1 and a second precoded signal z2, generating a first encoded block and a second encoded block using a predetermined error correction block encoding method, generating a baseband signal with M symbols from the first encoded block and a baseband signal with M symbols the second encoded block, and precoding a combination of the generated baseband signals to generate a precoded signal having M slots.

Methods, devices and algorithms for the linearization of nonlinear time variant systems and the synchronization of a plurality of such systems. One embodiment includes a transmit path, including the power amplifier, as used in wireless transmit systems. Advances made in CMOS technology, digital to analog converter (DAC) technology make it possible to implement a substantial part of such a system in the digital domain. Additional embodiments include the integration of a substantial part of such a transmit system in a single integrated circuit (IC). A digital implementation allows for linearization of a broad range of nonlinear and time variant effects. Another aspects is the reuse of methods, devices, components and algorithms used for the linearization of a transmit system to synchronize and time align multiple transmit systems.

Methods, devices and algorithms for the linearization of nonlinear time variant systems and the synchronization of a plurality of such systems. One embodiment includes a transmit path, including the power amplifier, as used in wireless transmit systems. Advances made in CMOS technology, digital to analog converter (DAC) technology make it possible to implement a substantial part of such a system in the digital domain. Additional embodiments include the integration of a substantial part of such a transmit system in a single integrated circuit (IC). A digital implementation allows for linearization of a broad range of nonlinear and time variant effects. Another aspects is the reuse of methods, devices, components and algorithms used for the linearization of a transmit system to synchronize and time align multiple transmit systems.

Consistent with the present disclosure, an encoder circuit is provided at a transmit side of an optical fiber link that maps an input sequence of bits of fixed length k a sequence of symbols of a codeword of length n, such that the symbols of the codeword define a predetermined transmission probability distribution. Preferably, each symbol of the codeword is generated during a corresponding clock cycle, such that after n clock cycles, a complete codeword corresponding to the input bit sequence is output. On a receive end of the link, a decoder is provided that outputs the k-bit sequence every n clock cycles. Accordingly, buffers need not be provided at the output of the encoder and the input of the decoder, such that processing of the input sequence, codewords, and output sequence may be achieved efficiently without large buffers and complicated circuitry. Moreover, the input sequence, with any binary alphabet may be matched to a desired output distribution with any arbitrary alphabet. Accordingly, probabilistic constellation shaping may be achieved over constellations of arbitrary size. In addition, relatively long codewords, may be encoded and decoded with the apparatus and method disclosed herein. Accordingly, for a fixed SNR a higher SE (more bits per symbol) can be achieved. Alternatively, for a fixed SE, a lower SNR may be sufficient. Moreover, the resulting SE may be finely tailored to a particular optical link SNR to provide data transmission rates that are higher than the low order modulation formats that would otherwise be employed for optical signals carried by such links.

Consistent with the present disclosure, an encoder circuit is provided at a transmit side of an optical fiber link that maps an input sequence of bits of fixed length k a sequence of symbols of a codeword of length n, such that the symbols of the codeword define a predetermined transmission probability distribution. Preferably, each symbol of the codeword is generated during a corresponding clock cycle, such that after n clock cycles, a complete codeword corresponding to the input bit sequence is output. On a receive end of the link, a decoder is provided that outputs the k-bit sequence every n clock cycles. Accordingly, buffers need not be provided at the output of the encoder and the input of the decoder, such that processing of the input sequence, codewords, and output sequence may be achieved efficiently without large buffers and complicated circuitry. Moreover, the input sequence, with any binary alphabet may be matched to a desired output distribution with any arbitrary alphabet. Accordingly, probabilistic constellation shaping may be achieved over constellations of arbitrary size. In addition, relatively long codewords, may be encoded and decoded with the apparatus and method disclosed herein. Accordingly, for a fixed SNR a higher SE (more bits per symbol) can be achieved. Alternatively, for a fixed SE, a lower SNR may be sufficient. Moreover, the resulting SE may be finely tailored to a particular optical link SNR to provide data transmission rates that are higher than the low order modulation formats that would otherwise be employed for optical signals carried by such links.

Embodiments of a method and a device are disclosed. In an embodiment, a method for operating a wired communications device involves including a frame boundary bit sequence and a random data sequence as a preamble of a bit stream, encoding the bit stream into an encoded bit stream, and transmitting the encoded bit stream using the wired communications device.