Qiu Duyu

Research on an efficient method of auto set of digital oscilloscope

The method of auto set makes it more convenient for users to capture and observe the unknown signal. It focuses on some related key technologies which are discussed in detail in the paper, such as initialize, judge whether all input channels are signaled or not, search vertical sensitivity by binary search method only if the channel has signal, set up the vertical sensitivity when multipath signals need to separate by the related software method, display the bias voltage, setup gear of time base according to the base-time system. And the experimental results are presented; the efficiency of complete design scheme is much higher than before.

Adaptive frequency-related mismatch calibration algorithm for TIADC

The frequency response mismatch among time-interleaved analog-to-digital converters (TIADC) systems different channels will degrade sampling accuracy. We propose a frequency mismatch algorithm, where compensation filter is designed basing on adaptive strategy. Adopted with this digital post-processing technique, the filter calibrates frequency-related mismatches effectively. Experimental results verify its effectiveness.

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.

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.