Showing papers on "Precision rectifier published in 1967"

Information detector employing a greatest-of detector

Abstract: 1,155,168. Transistor pulse circuit; pulse modulation systems. INTERNATIONAL BUSINESS MACHINES CORP. 10 April, 1968 [28 July, 1967], No. 17203/68. Headings H3T and H4L. A circuit for detecting the instant when pulses reach their peak voltage comprises a first circuit 2 (Fig. 5) for storing the peak valve of pulses, a parallel circuit 3, 4 for delaying the pulses and storing the peak valve of the delayed pulses and a comparator 5 which produces an output only when the two stored values are equal. As shown, the output of the comparator is used via transistors 24 to discharge the capacitor 22 of the peak detector 2 and via a variable delay circuit 6 to discharge the capacitor 42 of the peak detector 4, the variable delay being produced by a one shot circuit 65 followed by a circuit which differentiates the trailing edge of its output pulse. In Fig. 2 (not shown), 10 and 11 are the desired pulses and the rest are lower amplitude noise pulses. The output of the undelayed peak detector builds up as at B and the output of the delayed detector as at D. Just before 17 the two outputs are equal and the comparator produces an output 15 which resets the first output at 17 and subsequently the other at 19, equality during resetting being too brief to produce an output. The circuit may be preceded by a digitial switched filter to pass any input pulses corresponding to a desired code and by a self-clocking gate which opens in a region around the expected time of the signal (Figs. 3, 4 and 6, not shown). The circuit is applicable to pulse position modulated signals and the forward delay would be equal to the longest time before an information pulse is expected and the resetting delay less than half the frame period.

Inrush current limiting circuit for rectifier circuits with capacitive load

Abstract: A rectifier circuit with capacitive load in which means are provided for preventing inrush current on start-up, this being accomplished by controlling the firing time of a controlled rectifier in accordance with sensing the voltage across the capacitive load; timing is achieved by appropriately varying the charging rate of a regulating capacitor which is periodically discharged; parameter regulating means is superimposed and is effective, once the parameter in question reaches a predetermined range, to take over control of the regulating capacitor charging rate and to thereafter modify that charging rate in order to maintain the parameter in question at a predetermined value.

Firing circuit for semiconductive controlled rectifiers

Abstract: A firing circuit for semiconductive controlled rectifiers to be fired in sequence, characterized in that means are provided for storing energy at the gate of a controlled rectifier about to be fired from the drive pulse of the preceding rectifier, the stored energy being discharged into the gate of the rectifier about to be fired upon initiation of its drive pulse to supply momentary peak drive and prevent high local dissipation.

Diode parametric amplifier

Abstract: 1,089,048. Parametric amplifiers. MULLARD Ltd. Aug. 22, 1966, No. 37502/66. Heading H3B. In a diode parametric amplifier of the type disclosed in Specification 996,346 the seriesresonance of the diode is used to support the idler current and the series-resonant idler frequency circuit is completed through the reactive coaxial section and the impedance of the signal source. A varacter diode D, Fig. 1, is positioned at the junction of waveguide A and coaxial line E, the diode being connected to the centre conductor of the coaxial line proper via an impedance transforming line W the portion U of which is formed to provide a low-pass filter section which at the idler frequency forms a low-impedance reactive connection across the coaxial line. The other end terminal of the diode is connected to a coaxial short-circuited section Y which presents a short circuit at the idler frequency but an inductive reactance at the signal frequency. In operation pump energy is applied to the waveguide A tuned by piston B and having a cut-off frequency which is above the signal and idler frequencies. The signal to be amplified is applied along the coaxial line and the equivalent circuit, Fig. 3 (not shown) comprises a source connected in series with the diode and an inductor representing the inductance of the section Y and the inductance presented at the signal frequency by the filter section U. The idler frequency is substantially the same as the series-resonant frequency of the diode, the equivalent circuit Fig. 4 (not shown) comprising the diode inductance and capacitance and the signal source, the filter section U presenting a very small reactance represented by a capacitance connected across the signal source and the section Y effectively connecting one terminal of the diode to the earthy side of the source. In the arrangement of Fig. 5 (not shown) the filter section U has the large-diameter part adjacent the diode formed with an internal idler-frequency halfwave short-circuit choke section filled with a dielectric material. The equivalent circuit for the signal, Fig. 6 (not shown) is the same as that of Fig. 3 except that the inductance of the section 7 is replaced by the inductance of the choke and for the idler frequency is the same as that of Fig. 4. In the embodiment of Fig. 8 (not shown) the coaxial line E is formed with an impedance-transforming taper and at the end adjacent the diode the central conductor of the coaxial line is formed With a short circuit choke section one half-wavelength long at the idler frequency.

High sensitivity amplifier with peak detector and storage means

Abstract: A high sensitivity electrometer employing a capacitor to accumulate an electronic charge over a relatively long period and a first switch for coupling the charge to an operational amplifier over a short period. An inverting capacitively coupled amplifier drives a storage circuit comprising a peak detector and memory capacitor. A second switch synchronized with the first switch couples the storage circuit to the operational amplifier through a filter network to apply the stored peak voltage in the memory capacitor as a direct coupled electrometer input signal.

Device Applications of Charge Rectifiers

Abstract: Two circuit models of a semiconductor junction rectifier are presented. For times long compared to the effective minority carrier lifetime, the usual current rectifier concept obtains. For times short compared to the lifetime, a charge rectifier is better able to explain experimental results; reverse recovery is evidence of this. Viewed in this way, semiconductor junctions are suitable for certain types of digital information processing. Voltage gain is limited only by junction breakdown and driver capability but charge (current) gain is inevitably less than one. The amount of charge run-down is shown to depend on the time the information is in the circuit. Scan generators, shift registers, serial memories, and serial converters have been studied as examples of the wide range of applications for which these devices are suitable.