Abstract: A buffer is described which includes two gain stages which may be constructed of MOS devices, the first stage having a low noise characteristic and the second stage having a high current drive capability. The second stage is switched in circuit only when high current drive is needed so that the buffer otherwise exhibits the low noise characteristics of the first stage. A feedback network is also switched in circuit in a manner that maintains the buffer's loop gain substantially constant, whether or not the high current drive stage is in circuit.

Abstract: A stereo amplifier circuit which comprises a first circuit responsive to a first input signal and to a second input signal for generating a first output signal which corresponds to the potential difference between the first and second input signals, a second circuit responsive to the first and second input signals for generating a second output signal which corresponds to the potential difference between the second and first input signals, a third circuit responsive to the first and second input signals for generating a third output signal which corresponds to the sum of the first and second input signals. The third output signal contains signal components being antiphasic to the first and second input signals.

Abstract: The present invention relates to a driver circuit for use in connecting a source of RF drive voltage to a power amplifier stage. The driver is comprised of a transformer having a center tap, a first terminal connected to a first branch of the transformer and a second terminal connected to a second branch of the transformer. A first capacitor is connected between the source and the center tap. A second capacitor is connected across the first and second terminals. The first terminal is connected to the input of the amplifier and the dummy load is connected to the second terminal. The dummy load can be replaced by a second power amplifier stage having an input impedance similar to the input impedance of the first mentioned power amplifier.

Abstract: A four-terminal network selectively convertible into a low-pass, high-pass, band-pass, all-pass or band-stop filter comprises three cascaded stages each including an operational amplifier with a grounded noninverting input, the amplifiers of the first two stages being of the integrating type provided with capacitive feedback circuits. Resistive feedback connections extend from a main output A of the third stage to the inverting inputs of the first and third stages and from a relatively inverted output A' of the third stage to the inverting input of the second stage, their respective resistances R.sub.u, R.sub.v, R.sub.w determining the coefficients of the denominator in a biquadratic equation ##EQU1## where H(p) is the transfer function of the network and p=jf/f.sub.n is given by the ratio of an operating frequency f to a reference frequency f.sub.o. The coefficients of the numerator, which could be of either sign and may also be zero, are determined by supply resistances R.sub.a, R.sub.b, R.sub.

Abstract: A measuring amplifier device is provided with an input circuit producing different functions of an input signal in order to permit output signals in different measuring ranges to be produced. The circuit can be constituted by an operational amplifier having a feedback connection composed of a series arrangement of several elements each defining a particular measuring range together with subtraction stages forming signals corresponding to each range, or by a plurality of diodes or diode-resistor networks connected to divide the input signal between them and each defining a different measuring scale.

Abstract: Disclosed is a differential amplifier having a pair of input terminals and multiple output terminals. Various ones of the output terminals are selectively enabled in response to output selection signals. Within the amplifier is a first transistorized circuit which generates analog signals representative of any voltage difference between the input terminals. A second transistorized circuit within the amplifier couples these analog signals to selected ones of the output terminals in response to the output selection signals.

Abstract: A CATV system is described wherein distribution cables are provided with amplifying means spaced at uniform intervals therealong. The amplifiers are provided with an input tap and two output taps, the first of which provides the usual gain to provide an output level equal to the input level plus the attenuation suffered by the signal traversing the cable from the preceding amplifier. The second output is provided by each amplifier by tapping the output signal at the first output tap with a directional coupler and processing the signal through an equalizer and coupling the output of the equalizer through a second directional coupler to a second output terminal. The signal derived at the second output terminal is such that a second identical amplifier connected to it will produce in its first output the signal levels required in the feeder system, when the first amplifier is operated at the signal levels appropriate for the main trunk system.