A hybrid integrated trunk and subscriber line interface
A two-chip hybrid integrated trunk and subscriber line interface has been fabricated for voice and data applications. This paper will discuss features including a programmable battery feed with lightning protection, battery-reversal signaling, 2-4 wire conversion, loop closure detection and power down capability.
A high-voltage IC for a transformerless trunk and subscriber line interface
A new high-voltage, junction-isolated, complementary bipolar technology has been used to fabricate an IC for a transformerless trunk and subscriber line interface. The new technology provides both vertical p-n-p and n-p-n transistors with BV/SUB CE0/ greater than 60 V, betas of 100, and f/SUB T/'s of 200 MHz. It permits the straightforward op amp realization of a new op amp circuit configuration in transformerless line circuits. The new configuration uses the high-voltage IC plus some low voltage control circuitry to provide limited current battery-feed, loop-closure detection, reverse-battery signaling, two-wire to four-wire conversion, lightning protection, power-down capability, and longitudinal performance which is independent of the battery-feed current magnitude.
Representation of systems disturbed by wide band noise
In this paper, a method of handling and working with wide band noise is developed. We represent wide band noise as a distributed delay of white noise and use it to reduce a nonlinear system disturbed by wide band noise to a nonlinear system disturbed by white noise. An application of this reduction to a nonlinear filtering problem under a wide band noise disturbance is discussed.