A coarse tuning synthesizer for wireless communication includes a digital control unit, a digital-to-analog converter, and a comparator. The digital control unit includes an output node coupled to a first input node of a VCO (voltage controlled oscillator). The digital-to-analog converter includes a first node coupled to the first input node of the VCO. The comparator includes an output node coupled to an input node of the digital control unit. The comparator also includes a first input node coupled to a second node of the digital-to-analog converter and a second input node coupled to an output node of the VCO.

A variable gain phase shifter includes an I/Q generator and a vector summation circuit. The I/Q generator generates phase signals based on an input signal. The vector summation circuit adjusts magnitudes and directions of first, second, third and fourth in-phase vectors and first, second, third and fourth quadrature vectors, and generates an output signal by summing the in-phase vectors and the quadrature vectors, based on the phase signals, selection signals and current control signals. The vector summation circuit includes first, second, third and fourth vector summation cells and first, second, third and fourth current control circuits. The first and second vector summation cells adjust the directions of the first and second in-phase vectors and the first and second quadrature vectors. The third and fourth vector summation cells adjust the directions of the third and fourth in-phase vectors and the third and fourth quadrature vectors. The first and second current control circuits are connected to the first and second vector summation cells, and adjust an amount of a first current and an amount of a second current. The third and fourth current control circuits are connected to the third and fourth vector summation cells, and adjust an amount of a third current and an amount of a fourth current.

A variable gain phase shifter includes an I/Q generator and a vector summation circuit. The I/Q generator generates phase signals based on an input signal. The vector summation circuit adjusts magnitudes and directions of first, second, third and fourth in-phase vectors and first, second, third and fourth quadrature vectors, and generates an output signal by summing the in-phase vectors and the quadrature vectors, based on the phase signals, selection signals and current control signals. The vector summation circuit includes first, second, third and fourth vector summation cells and first, second, third and fourth current control circuits. The first and second vector summation cells adjust the directions of the first and second in-phase vectors and the first and second quadrature vectors. The third and fourth vector summation cells adjust the directions of the third and fourth in-phase vectors and the third and fourth quadrature vectors. The first and second current control circuits are connected to the first and second vector summation cells, and adjust an amount of a first current and an amount of a second current. The third and fourth current control circuits are connected to the third and fourth vector summation cells, and adjust an amount of a third current and an amount of a fourth current.

A ultra-high speed DAC apparatus (e.g., with a full sampling frequency not less than 20 GHz) may include one or more digital pre-coders and DAC modules. Each DAC module may include multiple current-mode DAC systems and a first power combiner. The gate length of transistors within each DAC module may be between 6 and 40 nm. Each current-mode DAC system includes a transmission line (e.g., 40 to 80 microns long) coupled to multiple interleaving sub-DAC systems (within the current-mode DAC systems) and the first power combiner. The first power combiner combines, without interleaving, analog signals that have been interleaved within the current-mode DAC systems. The impedance of the first power combiner matches the impedance of each of the current-mode DAC systems and a load of the first power combiner. A second power combiner combines, without interleaving, analog signals from the DAC modules.

A second-order modulator includes a plurality of integrators and a parallel higher-bit processing part, and the parallel higher-bit processing part includes a plurality of addition and determination processing sections. The addition and determination processing section receives first and second carry inputs and first and second state inputs, and outputs a quantized output and first and second state outputs. A first selector selects one set from sets of the first and the second state outputs from the plurality of addition and determination processing sections and outputs the selected set, and a second selector selects one quantized output from the quantized outputs from the plurality of addition and determination processing sections. An output of the first selector is used as a selection control signal for the first and the second selectors.

A second-order modulator includes a plurality of integrators and a parallel higher-bit processing part, and the parallel higher-bit processing part includes a plurality of addition and determination processing sections. The addition and determination processing section receives first and second carry inputs and first and second state inputs, and outputs a quantized output and first and second state outputs. A first selector selects one set from sets of the first and the second state outputs from the plurality of addition and determination processing sections and outputs the selected set, and a second selector selects one quantized output from the quantized outputs from the plurality of addition and determination processing sections. An output of the first selector is used as a selection control signal for the first and the second selectors.

A method of calibrating a delay generation circuit and the corresponding circuit.

A method of calibrating a delay generation circuit and the corresponding circuit.

The present application provides a vector quantization digital-to-analog conversion circuit, for converting a digital signal to an analog signal, characterized by includes a vector quantization circuit, configured to receive the digital signal and generate a vector quantization signal; a data weighted averaging circuit, coupled to the vector quantization circuit, including a plurality of data weighted averaging sub-circuits, configured to receive the vector quantization signal to generate a plurality of data weighted averaging signals; and a digital-to-analog conversion circuit, coupled to the data weighted averaging circuit, including a plurality of digital-to-analog conversion sub-circuits, configured to receive the data weighted averaging signal to generate the analog signal.

The present application provides a vector quantization digital-to-analog conversion circuit, for converting a digital signal to an analog signal, characterized by includes a vector quantization circuit, configured to receive the digital signal and generate a vector quantization signal; a data weighted averaging circuit, coupled to the vector quantization circuit, including a plurality of data weighted averaging sub-circuits, configured to receive the vector quantization signal to generate a plurality of data weighted averaging signals; and a digital-to-analog conversion circuit, coupled to the data weighted averaging circuit, including a plurality of digital-to-analog conversion sub-circuits, configured to receive the data weighted averaging signal to generate the analog signal.