The Discrete-Time Convolution Model behavioural approach is proposed for the characterization/empirical modelling of high-performance broad-band A/D channels, designed for the acquisition of signals approaching the microwave field. Thanks to its inherent capability of separately describing all the nonidealities of different nature within the channel, and in particular the non-linear dynamic effects, the method is particularly suitable for the A/D channels of modern high-frequency instrumentation and RF receivers. Experimental results are provided, which validate the analytical formulation of...
In the recent years, a universal measurement setup for high-resolution ADC testing at the frequency band of 0.5 - 20 MHz was designed and prototyped at the Czech Technical University. Parameters of harmonic signal are analysed in contribution, which is needed for inverters testing and further a construction of a special generator with high spectral purity is described.
The main problem of the high resolution ADC testing within the frequency range hundreds of kHz to tens MHz is the spectral purity of testing signal. Commercially produced low-distortion generators have the spectral purity sufficient for testing of ADC app. up to 16 bit, analogous to sensitivity of commercial analyzers for measuring of signal quality is enough for check of signal with of signal spectral purity for testing of ADC app. up to 16 bit. There is necessary to use special methods for measuring of special signal sources with extreme high spectral purity that are designed with higher...
A D/A subconverter (DASC) error correction scheme based on weighting capacitor rotation is adapted to account for finite op-amp gain. Simulations show that reasonable estimates of capacitor mismatch can be obtained even if the actual gain is replaced by a nominal gain differing by as much as a factor of two. DASC capacitor mismatch might therefore be estimated in the foreground at power-up, and most part of the correspondingmismatch noise and mismatch-induced interstage gain error might be cancelled, possibly delegating to a background calibration the task of correcting the remaining...
This paper describes a cyclic time domain successive approximation (CTDSA) architecture that can be used as an interpolator in a time-to-digital converter (TDC). The new architecture of the CTDSA achieves adjustable sub-ps-level resolution with high linearity in ns-level dynamic range. The propagation delay adjustment is implemented by digitally controlling both the unit load capacitors and the discharge current of the load capacitance using current DAC. The proposed CTDSA achieves 610 fs resolution and ~2.5 ns dynamic range. The total simulated power consumption is 25.8 mW with 5 MHz...
In this paper the qualities of short methods for testing dynamical parameters internal ADCs and DACs with impulses Multi-Tone and Sinx/x signal are analyzed. Practically examples are compared with standard Single-Tone Fourier Transform Test Method. This methods finds an application in the industry in less demanding economical short testing.
We present a time-to-digital converter with a virtual time coding line created as an equivalent of two independent time coding lines operating simultaneously. Proposed solution allows to overcome the technology limitation in achievable resolution and improve the precision of conversion. The new coding line used in the interpolating time counter designed in an FPGA CMOS device provides the precision (standard deviation) below 35 ps within a 1 s measurement range.
The paper presents the possibility of an adaptive A/D conversion with the non-uniform exponential tracking procedure. It has been shown that the proposed A/D conversion gives better results than the classical A/D conversion with the successive approximation procedure due to b -times more available sampling points. Taking into consideration only the quantization noise contribution the adaptive A/D conversion performs better results if the sampling ratio s is high enough.
A diagnostic system being designed to measure the beam phase and energy of the Drift Tube Linac (DTL) in the Proton Accelerator of China Spallation Neutron Source (CSNS) is described and the characterization of the prototype is presented. The signals received from Fast Current Transformers (FCTs) are Radio Frequency (RF) signals with the frequency up to 350 MHz and a dynamic range of -30 dBm to 3.5 dBm. The RF signals are converted to orthogonal streams directly with the In-phase and Quadrature-phase (IQ) undersampling technique based on high-speed high-resolution A/D conversion. Thus a high...