1123-A

The General Radio 1123-A Digital Syncronometer was introduced in Catalog S (1965) and remained available until Catalog U (1970).

It is basically a digital clock with circuits that enable it to be synchronised with standard time signals, originally intended to be used in conjunction with an 1124 time signal receiver system.

The 1123-A has three digitally delayed outputs, with delays selectable by thumbwheel switches.

To check the frequency of a signal (e.g. a 1 MHz standard), that frequency it is divided down and used as an external reference to the 1123-A.

The first sync output is used to trigger an oscilloscope, which displays the Loran C (or WWV signal). The delay of the second pulse is adjusted with the 1123A controls to be coincident with a peak or a zero crossing of the reference signal, e.g. Loran-C.

A pulse train derived from the 100-kHz input is divided down to produce a 1-pulse-per-second master tick and timing pulses at 100 kHz, 10 kHz, 1 kHz, 100 Hz, 10 Hz, 1 Hz, and 0.1 Hz. These signals also operate a five-digit recognition circuit to produce an 8-millisecond pedestal, occurring at 1 pps. This pedestal can be delayed by a precise amount of time with respect to the master tick, 0.00000 through 0.99999 s selected by thumbwheel switches.

Pedestal and a sync pulse are provided for comparisons of the master tick with WWV-type transmissions on an oscilloscope screen. For intercomparisons where greater time resolution is possible (e.g., Loran C), a 1-MHz input is used to drive a delay circuit (0 to 9 microseconds in 1-microsecond steps, 0 to 1 microsecond continuously), which produces a 0.2- microsecond marker controlled by the last two front-panel thumbwheels.