Automated Measurement System for T1 Characterization

As part of the T-Carrier characterization program, T1 repeater section performance measurements were performed in 1977 and 1978. In this paper, we describe the experimental design and equipment implementation for these measurements. Other aspects of this program are described in companion papers. 1 The T1 repeatered line consists of the regenerative sections adjacent to central offices (end sections), and the intermediate sections. Intermediate section measurements performed at manholes are discussed in Section 2 and end-section measurements in the central office are described in Section 3. The following measurements were performed for each intermediate section: (i) Line resistance and simplex power currents (ii) Longitudinal ac current (iii) Pair insertion loss at various frequencies (iv) Crosstalk coupling losses within the apparatus case slot (v) Crosstalk power sum (vi) Line margin for a test repeater (vii) Bit-rate and half-bit-rate output power of transmitting repeater 1005 (viii) Crosstalk spectrum at repeater input (ix) Automatic line buildout current of test repeater (x) Voltage amplitude distribution of crosstalk noise (xi) Service repeater margin and eye opening (xii) Test repeater calibration checks End sections were characterized by measuring crosstalk power sum, crosstalk margin, and voltage amplitude distribution of crosstalk using separate test equipment designed for single-ended measurements in the central office.