Improvements in or relating to a monitoring arrangement for a p.c.m. communication system

摘要

1,100,880. Monitoring P.C.M. systems. GENERAL ELECTRIC CO. Ltd., 11 July, 1966 [9 July, 1965], No. 29202/65. Heading H4L. In a monitoring arrangement for a P.C.M. communication system, a plurality of successive digits are stored periodically in stores 1 (at the coder or decoder) whose outputs are supplied to integrators 2. With the natural binary code, in which one half of the code representations of a range of magnitudes constitute a reflected image of the other half, the average level of the audio signal being aligned with the centre of the code range, each digit will have each of its two values for approximately half the total time when this total time is large compared to the period of the lowest frequency component of the audio signal. Consequently the positive and negative outputs from each of the integrating circuits 2 will be equal with normal operation. These positive and negative signals are supplied to gates 3 and 4 respectively and should a discrepancy occur one or other of the voltage-responsive devices 5, 6 will operate an alarm 7. The arrangement may be modified for other binary or other than binary codes.