摘要:
This disclosure is directed towards techniques and methods of suppressing the effect of modulated clock jitter in a digital to analog conversion (DAC) circuit of a polar modulator in a transceiver. A phase locked loop (PLL) in a modulator circuit may introduce a deterministic jitter in DAC generated pulses which may lead to amplitude variations in the DAC generated pulses. The clock jitter may change the duty cycle of the input amplitude to the DAC which may result in a variation of the output of the DAC generated pulse. A digital pre-distortion or digital multiplier circuit may be introduced before the DAC circuit to increase or decrease the DAC amplitude to compensate for the pulse width modulation.
摘要:
In one implementation, a polar transmitter includes a digital signal processing component that processes baseband signals and provides a baseband data signal with amplitude values; and a digital pre-distortion component that receives the baseband data signal with amplitude values, compensates for jitter error in the baseband data signal with amplitude values, and provides an adjusted modulated signal.
摘要:
This disclosure is directed towards techniques and methods of suppressing the effect of modulated clock jitter in a digital to analog conversion (DAC) circuit of a polar modulator in a transceiver. A phase locked loop (PLL) in a modulator circuit may introduce a deterministic jitter in DAC generated pulses which may lead to amplitude variations in the DAC generated pulses. The clock jitter may change the duty cycle of the input amplitude to the DAC which may result in a variation of the output of the DAC generated pulse. A digital pre-distortion or digital multiplier circuit may be introduced before the DAC circuit to increase or decrease the DAC amplitude to compensate for the pulse width modulation.
摘要:
Embodiments provide a DC-DC converter (DC-DC=direct current to direct current) for envelope tracking. The DC-DC converter includes a digital control stage and a driving stage. The digital control stage is configured to provide a digital control signal based on digital information describing an amplitude of a digital baseband transmit signal. The driving stage is configured to provide a supply voltage for an RF amplifier (RF=radio frequency) based on the digital control signal.
摘要:
One example described herein relates to a digital to analog converter (DAC). The DAC includes a digital signal input configured to receive a multi-bit digital input signal, and a plurality of cells arranged in rows and columns. Each cell includes a current source. A row decoder and a column decoder provide respective control signals to respective rows and respective columns to selectively couple a number of the current sources to an output of the DAC. The number of current sources which are coupled to the output by the control signals is dependent on the multi-bit digital input signal. At least one of the control signals is modulated based on a local oscillator signal.
摘要:
This disclosure relates to a compensating for nonlinearity resulting from a capacitance feedback in current cells of a single ended digital to analog circuit.
摘要:
The present invention provides a digital-analog converter having: a DEM logic device (10) for generating at least two digital output data items (13, 14) from the digital input data (11) on the basis of a predetermined algorithm to determine an initial cell and a final cell in the array arrangement (22), between which there are situated cells (24) with energy sources (30) to be activated; a decoder device (16) for decoding the at least two digital output data items (13, 14) from the DEM device (10) into actuation signals (17, 17′, 18, 18′, 19, 19′ 20, 20′, 21, 21′) in order to activate the cells (24) which are to be activated; and an array arrangement (22) of cells (23) for outputting at least one quantized analog signal (25, 25′) on the basis of the actuation signals (17, 17′, 18, 18′, 19, 19′ 20, 20′, 21, 21′). The present invention likewise provides a method for digital-analog conversion.
摘要:
During A/D conversion of time-discrete analog input values, a quantizer is used in which an analog quantization error is obtained after every conversion. The quantization error is stored in a buffer, and fed back through a subtracter to at least one input value of a subsequent conversion. The quantizer has a conversion frequency, which is more than double the maximum frequency contained in input values, so the conversion operates in an oversampling mode. During feedback the quantization errors of several conversions, prior to a varying number of conversions, are preferably fed back to an input value. The invention can be used with all conventional quantizers, for which an analog quantization error can be obtained, so it is possible through a noise shaping procedure to shift quantization noise into higher-frequency spectral ranges to improve the signal-to-noise ratio or reduce the quantization noise in a useful spectral range.
摘要:
The oscillator circuit has a first and a second circuit node and a parallel circuit of a quartz resonator, a first inverter, and a first resistor element connected between the circuit nodes. The first circuit node is connected to a reference potential via a first capacitor circuit, and the second circuit node is connected to the reference potential via a second capacitor circuit. The first capacitor circuit has at least two capacitors whose first electrode is connected to the reference potential, and whose second electrode is connected to the first circuit node via one switching element each. Furthermore, the oscillator circuit has a precharging circuit for precharging the capacitors, and a synchronizing circuit for switching in the capacitors at an instant in which the precharging potential corresponds to the potential at the first circuit node.