Pan Huiqing

Key technology design of 6 GSPS high-speed digital storage oscilloscope

With the growth of the ADC sampling bandwidth and the DSP theory and techniques becoming more sophisticated, the time-domain test based on real-time sampling, such as digital storage oscilloscope, is emerging to the mainstream of electronic test development, and also gestating the important transformation on electronic instrumentation systems. However, the extreme dependence on sampling rate and the rapidly inflated amount of information processing already become the time-domain tests bottleneck, and it greatly restricts the broadband time-domain test equipments development and application. This paper introduced design method of a broadband high speed digital storage oscilloscope, including design objectives, the overall scheme and work flow, and accessed the results of the experimental testing and analysis.

Study on signal conditioning technology in 2GHz broadband digital oscilloscope

Its the trend of electronic development to test the broadband signal. The channels of frond-end broadband signal conditioning constitute the key for the high-speed digital oscilloscope, in other words, the performance of such conditioning channels will determine the signal acquisition capacity of digital oscilloscope. In combination with the specific signal conditioning requirements, the paper describes the design of functional circuit for the high-speed digital oscilloscope, which includes broadband impedance transfer circuit, variable gain circuit, high-speed parallel drive circuit and high-speed trigger circuit. The major technologies of broadband signal conditioning is further analyzed. In view of the experience of practical system commissioning, the DC-2GHz broadband signal conditioning test is feasible. The design could be suggested to use in other broadband instruments.

Optimal design of adjustable frequency response linear-phase filters

A digital linear-phase finite-length impulse response (FIR) filter design method is proposed, which has adjustable frequency response. For this purpose, Farrow structure is employed in which the overall transfer function is a weighted linear combination of fixed subfilters and where the weights are directly determined by the input parameter. Optimal design technique is introduced which generates globally optimal overall filters in the Chebyshev sense over a whole set of filter specifications. An example is included in the paper to demonstrate the effectiveness.

Nonuniform mismatches compensation algorithm for time-interleaved sampling system using neural networks

Time-interleaved sampling system increase the overall sampling rate by combining multiple slow ADCs. However, its performance suffers from several mismatches. This paper introduces a BPNN-based compensation method to deal with the automatic compensation of timing skew, gain and offset mismatches simultaneously, and track the time-varying errors self-adaptively. Simulation results show that the calibration technique can greatly attenuate the spurs and the SFDR can be significantly improved by 27–58 dB, and it demonstrates the efficiency of proposed method.

Design and realization of compensation for one type of broadband acquisition channel

Bandwidth of analog channel is one of the key factors that restrict the escalation of performances of digital storage oscilloscope. The performances of wideband analog channel are affected by various factors such as features of separation components, distribution parameters and input bandwidth of high-speed ADC, etc. The article analyzes in detail various factors that have influence upon bandwidth in hardware circuit from the perspective of system level, and has put forward related solutions for improvement; In conjunction with frequency domain compensation theory, and by taking reference of Gaussian frequency response curve, and through digital compensation to analog channel by way of algorithm, compensation results are obtained and are presented in the article. Test results demonstrate that −3dB bandwidth of the whole unit is higher than 1GHz. Method given in the article can also be extended into wide ranges of wideband testing instrument such as signal generator, and spectrum analyzer etc.