Method of and apparatus for testing transmission line carrying bipolar PCM signals

US3965294A · kind A · utility

Assignee

• Wandel U. Goltermann

Inventors

• Gunter Renz · Pfullingen, DE
• Walter Wehr
• Bertram Amann

Key dates

• Filing date: Apr 23, 1975
• Grant date: Jun 22, 1976
• Expiry date: Apr 23, 1995

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L25/4925
• WIPO field: Digital communication
• WIPO sector: Electrical engineering

Abstract

To check the bit-distortion ratio of a transmission line carrying bipolar PCM signals, converted from a binary to a balanced ternary code at the tramsmitting end and reconverted into binary signals at the receiving end, binary test words and identical reference words are simultaneously read out from storage at opposite ends of the line. The test words are converted into bipolar form, for transmission, and the received pulses are distributed according to polarity over a first pair of leads while the binary pulses of the reference words are distributed over a second pair of leads according to the conversion code used at the transmitting end. The pulse trains on corresponding leads are compared, bit by bit, in a deviation monitor whose output, in response to any mismatch, advances a reversible counter which is reverse-stepped by timing pulses of a cadence reduced by a frequency divider to a fraction of the bit rate. If the error rate exceeds that fraction of the bit rate, the counter reaches an alarm position in which it emits an enabling signal allowing a polarity comparator to switch the local pulse distributors while letting a polarity-independent pattern comparator arrest the read…