GB1121406A - Recording devices, such as oscillographs - Google Patents

Abstract

1,121,406. Pulse circuits. SIEMENS A.G. 23 Aug., 1966 [23 Aug., 1965], No. 37845/66. Heading H3P. A circuit for processing input signals into trigger pulses suitable for triggering the time base of an oscilloscope comprises a pair of parallel channels A, B, having specified components. As described, each voltage-sensitive gate 2, 3 is responsive to bipolar pulses greater than a minimum threshold in one position of switches U2, U3 and to monopolar pulses in the other setting of U2, U3. Blocks 2, 3 may be formed by differential amplifiers having their thresholds controlled by potentiometers P2, P3 and switch S. Shaping circuits 6, 7 provide a pulse each time the input signal to the appropriate gate 2, 3 reaches an upper or lower threshold level. The circuit has four different modes of operation dependent on the settings of switches S1 ... S4 as shown in Fig. 2. When it is desired to examine only a part of a waveform, switches S1, S4 are closed and an auxiliary output from the circuit fed as intensity modulation to the grid of the cathode-ray tube. A bright marker spot will thus be visible on the tube and may be adjusted by control t v of delay device 1 so as to coincide with the interesting part of the waveform. Switch S1 is now opened and S3 closed so the time base will then start at the point selected by t v . The time base may alternatively be triggered in a " range-dependent " manner, i.e. only by input signals within upper and lower limits determined by threshold gates 2, 3 by closing switches S2, S. Bi-stable circuit 4 is set by a pulse derived when the input voltage passes a lower threshold, initiating operation of the delay device 1. If the input voltage exceeds an upper threshold, a second pulse from 6 or 7 resets the bi-stable device 4 and inhibits any output from 1.