Abstract: An automatic equalizer is described including a first transistor to the input of which a cable is coupled and which is branched in common emitter configuration and a second transistor branched in common collector configuration a collector of the first transistor being coupled to the base of the second transistor and the emitters of the transistors being intercoupled through a positive feedback circuit. In variation by small variation of a variable which is substantially independent from active parameters of the transistors results in a gain variation which is independent of the cable length in the lower frequency region and utilizes no coils.

Abstract: An amplifier whose transmission factor is to be controlled as a function of a control voltage and including an amplifier member having a negating input, connected to have its impedance varied by the control voltage and an electronically controllable variable impedance having one side connected to the amplifier member output, a second impedance connected between the other side of the first impedance and ground, and a switch assembly for switching the connections within the amplifier between two operating states providing mutually complementary control characteristics, the amplifier member output providing the amplifier output in one operating state and being connected to the negating input in the other operating state, and the point of connection between the impedances being connected to the negating input in the one operating state and providing the amplifier output in the other operating state.

Abstract: A variable equalizer adapted to be fabricated in an integrated circuit structure and having improved compensation characteristics comprises a parallel connection of two circuits, one including a series connection of a first impedance circuit (impedance: Zy) and an input A.C. signal source circuit having a voltage v.sub.i, the other comprising a series connection of a second impedance circuit (impedance: Z.sub.x) and an A.C. signal source circuit having a voltage amplitude v.sub.z which is equal to v.sub.i (K/Z.sub.y).sup.2, where K is a constant, and the second impedance circuit, consists of a variable resistor.

Abstract: An amplifier circuit for the unadulterated transmission of phase information of a supplied ac voltage signal over a large dynamic range includes a series connection of a series of similar amplifier stages each of which is followed by a symmetrical limiter. The amplifier operates as a logarithmic amplifier for maintaining the amplitude information of the supplied ac signal. Each of the amplifier stages comprise an emitter-base transistor amplifier circuit having negative feedback and an output circuit which contains a resonant circuit which is strongly damped by an attenuating resistor and whose capacitance is formed by a trimmer capacitor connected in parallel to a pair of diodes. The diodes are connected in anti-parallel relation to one another and represent the limiter. The capacitance is adjustable for purpose of impedance adjustment and is set in such a manner that the resultant resonant circuit impedance is capacitive.

Abstract: A cable equalization resonant amplifier circuit for compensating for the signal-attenuation effects of a coaxial cable connected with the amplifier circuit and having a length of up to one-half mile. The gain of the amplifier circuit is matched with the attenuation characteristics of the coaxial cable over a wide range of frequencies by employing an LC resonant circuit with a Q of approximately 1 in the emitter circuit of an amplifying transistor. The gain for the amplifier circuit is established to match the attenuation characteristics of the coaxial cable at low frequencies by an RC circuit coupled with the amplifying transistor and the LC resonant circuit. The maximum or peak desired value of gain for the amplifier circuit at the resonant frequency of the LC resonant circuit is established by a resistor connected in series with the LC resonant circuit and a resistor in the collector circuit of the amplifying transistor.

Abstract: An improved circuit permits measurement of the impedance of an Al.sub.2 Ob.3 water vapor sensor used with conventional radiosonde telemetry systems.The circuit includes an oscillator, an output pulse shaper and a voltage regulator. The oscillator section is a temperature stabilized feedback oscillator which uses the sensor as a feedback element. The oscillator output is a square wave varying from 20 to 200 Hz over a dew point range, of 110.degree. to 0.degree. C. and is stable within .+-. 1% over a -60.degree. to +20.degree. C. temperature range. The output pulse shaper converts the square wave from the oscillator to a 60 microsecond wide, 3 volt negative-going pulse suitable for modulating the radiosonde transmitter. The voltage regulator provides regulated +4.5 volts from the sonde battery for operating the oscillator and pulse shaper.

Abstract: A so-called charge sensitive amplifier is used as a pre-amplifier for a semiconductor detector. A field-effect transistor (FET) is used as the input stage of the amplifier, wherein the gate terminal of the FET is fed back from the output of the amplifier and the drain terminal of the FET is grounded through a capacitor and connected to a constant current source to make the drain voltage change correspond to the gate potential. The gate potential is self-stabilized.