Characterizing high-speed oscilloscopes
Article Abstract:
Hewlett Packard (HP) has developed a technique to measure rise times of the fastest oscilloscopes by recognizing a short switch closure consisting of a few picoseconds between the signal at the input of the oscilloscope and the detection circuit's holding capacitor. During the switch closure, a sampling current is collected and measured with an analog-to-digital converter. The sampling current creates an electric disturbance signal that, while not identical, is very similar to the oscilloscope's response impulse. HP's measurement technique theory is to assume the sampling circuit's impulse response and input disturbance signal are identical and thus measure the pulse disturbance with a second identical sampler and produce a waveform composite of the two identical responses.
Publication Name: IEEE Spectrum
Subject: Engineering and manufacturing industries
ISSN: 0018-9235
Year: 1990
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Oscilloscopes: how to find the one that fits
Article Abstract:
The different types of oscilloscopes available vary in the number of signal channels, data storage capacity, and length of data records, as well as in speed, triggering capability, and identification of glitches. The choice of the instrument depends on the application for which it is intended. The values for all significant parameters are discussed for several applications, and different manufacturers' products are reviewed. The speed of CRT tubes is also important for the display of the inherent bandwidth advantage of an analog scope for very fast single events. The variation in price depending on relative bandwidth is explained. Automatic setup times and training, as well as PC-like menus, are also examined.
Publication Name: IEEE Spectrum
Subject: Engineering and manufacturing industries
ISSN: 0018-9235
Year: 1987
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Two ways to catch a wave: digital oscilloscopes can compete with the best analog types, abetted by a-d converters that run at 4 gigasamples per second
Article Abstract:
The analog-to-digital converter is significantly boosting the performance of digital oscilloscopes, pushing their digitizing rates to four gigasamples per second at eight bits of resolution. Analog oscilloscopes provide adequate bandwidth in most measurement applications, and they offer usually responsive and clear screen views. An experienced engineer analyzes the analog scope's gray-tone levels; brighter areas indicate the path the signal follows more often, dimmer areas indicate the paths less traveled. HP was the first company to successfully bridge the gap between the analog and digital scope at digitizing and recording rates of four Gsamples/s. Challenges in developing the technology are discussed.
Publication Name: IEEE Spectrum
Subject: Engineering and manufacturing industries
ISSN: 0018-9235
Year: 1993
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