High frequency sampler trigger circuits including signal feedback to regulate switching times of trigger circuits

摘要

1,030,102. Cathode-ray tube circuits. HEWLETT-PACKARD CO. Feb. 8, 1964 [Feb. 28, 1963], No. 6817/64. Heading H4T. In a circuit for producing a slowly-varying display signal from a number of amplitude samples taken at different instants along a rapidly recurring waveform, the signal to be sampled is supplied via resistors 15; 17 to a balanced tunnel diode circuit 9, 11 supplied with oppositely going ramp signals 43, 53 respectively from a generator 41. With no - input signal the ramp signals cause the tunnel diodes to switch operating states at the same time and the resulting signals when combined in resistors 19, 21 produce no signal at the input of amplifier 23. A signal at the input terminal having, for example, an instantaneous positive polarity will be combined with the two ramp signals so that the tunnel diode 11 will switch to its high voltage condition state earlier and the tunnel diode 9 will switch to its high voltage conduction state later than would occur in the absence of an input signal. Thus the duration of the pulse applied to the amplifier 23 is determined by the amplitude of the input signal the pulse being terminated by the change of state of tunnel diode 9. The output of the amplifier is supplied via a gate 25 and stretcher 27 to a utilization device 55, e.g. a cathode-ray tube, the gate being controlled by a time base generator 57 so that the reset cycle of the tunnel diodes does not affect the output signal. The stretcher 27 includes an integrating circuit converting the width modulated pulses to a corresponding amplitude modulated pulse. The output of the stretcher 27 is also supplied as negative feedback via resistors 29, 31 respectively, to the tunnel diodes. The tunnel diodes may be replaced by blocking oscillators or Schmitt trigger circuits.