Modeling of the HP-1430A feedthrough wide-band (28-ps) sampling head

Abstract

The theory and construction of the HP-1430A feedthrough sampling head are reviewed, and a model for the sampling head is developed from dimensional and electrical measurements in con junction with electromagnetic, electronic, and network theory. The model was used to predict the sampling-head step response needed for the deconvolution of true input waveforms. The dependence of the sampling-head step response on the sampling diode bias is investigated. Calculations based on the model predict step response transition du rations of 27.5 to 30.5 ps for diode reverse bias values of -1.76 to -1.63 V.

Effects of nonlinear diode junction capacitance on the nose-to-nose calibration

“…We implemented the 20-GHz sampling circuit described in [7], [8] in SPICE, neglecting any packaging parasitics, input networks, or filtering at the input of the sampler in order to concentrate on the effect of the nonlinear capacitance. We used a common model for a Schottky-barrier diode [8], [9] in which the diode conductance is in parallel with a time-varying, voltage-dependent junction capacitance.…”

“…1. It is based on a model for a 20-GHz oscilloscope [7], [8]. The simplified output circuit consists of a charge amplifier that sums the charge stored on the hold capacitors during each sampling cycle, as shown in Fig.…”

Waveform metrology: signal measurements in a modulated world

“…Unfortunately, such ideal pulse sources do not occur in practice and sources with sufficiently short duration (i.e. high bandwidth) to approximate a delta function have long been sought [17,18,44,45,51]. Frustrating this search, is the observation borne out over time that innovations either in signal generation or signal measurement are very quickly adopted by the other side.…”

50 years of RF and microwave sampling

“…Another analysis was detailed by Grove in 1966 [39]. The 1430A was extensively studied by Riad before 1978 [40] and finished for journal publication in 1982 [41]. He disassembled a 1430A sampling head and measured the dimensions of the transmission lines, as well as the internal cavity.…”