Browse Prior Art Database

Digital Waveform Analyzer

IP.com Disclosure Number: IPCOM000090805D
Original Publication Date: 1969-Jul-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Bova, TB: AUTHOR [+2]

Abstract

The analyzer provides an accurate analysis of complex waveforms. Analog analysis of such waveforms at low repetition rates encounters drift problems that are difficult to compensate for. This digital waveform analyzer eliminates DC drift problems and provides resolution of rapid waveform transitions to the required degree of accuracy. The analyzer is used to test a magnetic recording head represented as wave generator 10. For each of the sampled portions X, Y, and Z of waveform 11, three digitized readings A, B, and C, are made. By comparison of the magnitudes of the three successively made readings, the shape of waveform 11 is determined as well as its amplitude.

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Digital Waveform Analyzer

The analyzer provides an accurate analysis of complex waveforms. Analog analysis of such waveforms at low repetition rates encounters drift problems that are difficult to compensate for. This digital waveform analyzer eliminates DC drift problems and provides resolution of rapid waveform transitions to the required degree of accuracy. The analyzer is used to test a magnetic recording head represented as wave generator 10. For each of the sampled portions X, Y, and Z of waveform 11, three digitized readings A, B, and C, are made. By comparison of the magnitudes of the three successively made readings, the shape of waveform 11 is determined as well as its amplitude.

At sampled portion X, there is a decreasing radius in waveform 11. The difference between readings A and B is less than the difference between readings B and C. Portion X is defined as occurring when the sum of readings A and C is less than twice center reading B. Portion Y is on the linear portion of waveform 11. The difference between readings A1 and B1 is equal to the difference between readings B1 and C1. The sum of readings A1 and C1 is equal to twice reading B1. Point 2 is on an increasing radius of waveform 11. The difference between readings A2 and B2 is greater than the difference between readings B2 and C2. The two of readings A2 and C2 is greater than twice reading B2. The doubling function is accomplished by shifting the contents of a binary register containing the B reading one place toward a more significant digit. The method repetitively makes sets of three successive measurements to ascertain the waveshape.

Sequencer 12 includes a three-state control for successively causing A register 13, B register 14, and C register 15 to receive the digitized values of the readings being mode. This arrangement divides readings into sets of three readings. The digitizing of the readings for insertion into the registers 13...15 is accomplished by test ramp circuit 16 energizing generator 10 to produce waveform 11. Synchronized with it by a synchronizing signal, supplied over line 17 by sequencer 12, is sampling ramp generator 18. The period of generator 18 output signal is short, 1/100, for example, compared with the generator 16 output signal. Clock pulses supplied over line 23 to opened And cause counter 24 to count the elapsed time from the occurrence of sync signal on line 17 to the time when comparator 19 detects coincidence in amplitude between waveform 11 and the ramp output from generator 18.

The output signals of generators 10 and 18 are supplied to amplitude comparator 19. This keeps And 21 e...