Abstract: An unconditionally stable impedance matching network for matching a nonloaded voice frequency transmission line to the standard impedance of a repeater on said line is provided.

Abstract: An improved monolithic piezoelectric bandpass filter unit, suitable for single side band applications, having a pair of finite poles introduced into one of its stopbands.

Abstract: An optical transmitter suitable for analog transmission in optic fiber communication systems utilizes two matched light emitting diodes to achieve distortion reduction.

Abstract: A pulse duration correcting circuit comprising a comparator and a bipolar averaging circuit for correcting the duration of incoming pulses to a desired standard value is disclosed.

Abstract: A limiter circuit for the extracted timing signal in high speed digital repeaters is disclosed. The conventional emitter-coupled transistor pair limiter is modified by applying to the base of the output transistor the decoupled, attenuated, and delayed signal at the collector of the input transistor. The delay is such that the compensating signal at the base is out-of-phase with respect to the input signal by approximately -5/2.pi.. Experimental determination of delay and attenuation yields optimal phase and amplitude responses which are a significant improvement over those of the conventional limiter.

Abstract: A self-adjusting voice frequency repeater for subscriber loops of varying ohmic resistances utilizing a multiplier-divider arrangement is disclosed.

Abstract: An improved monolithic piezoelectric filter unit having two bilateral electrodes on one surface and a common electrode on the opposite surface, the common electrode connected to the common terminal of the filter unit via a capacitor.

Abstract: A pair of interchangeable memories is provided, one of which receives a PCM frame while simultaneously transmitting one, while the other of which, containing the previous frame, outputs the channel bits for parallel processing. Each simultaneous conference is assigned a temporary storage location in which the associated channels are accumulated to yield the total conference signal. Subsequently, each channel is subtracted from its conference total to produce the final conference signal. The final conference signals replace the unprocessed frame in the memory where, at the end of the current frame, it is interchanged with the other memory. And so on.

Abstract: A temperature compensated helical resonator structure having a rigid dielectric filling between helix and shield of a material with a negative thermal coefficient of permittivity. The filling provides shock resistance by preventing the helix from vibrating, while simultaneously aiding in thermal compensation.

Abstract: Two digitally controllable attenuator networks are provided in the receiver and transmit channels of a loudspeaking telephone system. The analog control signal usually utilized to control the total loop gain in such systems is converted to a digital representation and its complementary representation, one of which is then applied to control the transmit attenuator and the other to control the receive attenuator. Stable, thump-free control of the loop gain is thus achieved.