Arbiter Systems 1092A, Operation Manual

Page: 69 / 214

8.3 Output Signal Description 51
Drive Current, mA Actual Drive Voltage, Vpp
0 4.5
1 4.48
10 4.3
100 2.54
Table 8.1: Drive Current vs. Voltage
8.3 Output Signal Description
All clock models can provide three different digital signals and one analog signal. Digital signals
consist of unmodulated IRIG-B, 1 PPS and Programmable Pulse. Analog consists of modulated
IRIG-B. 1 PPS is often used to synchronize another (unsynchronized) timing signal. Programmable
pulse modes are similar to 1 PPS only they have an adjustable period and pulse width with the
rising edge on time. Programmable pulse modes include, seconds per pulse, pulse per hour, pulse
per day, single trigger (once per year) and slow code. Pulse polarity adjustment is also available.
8.3.1 IRIG-B Description
IRIG-B is a complete serial time code that occurs once per second and, depending on the config-
uration, contains the day of year, hours, minutes, seconds, year and other important information.
The Model 1092A/B/C and 1093A/C transmit (IRIG) Format B with four variations as seen in
Table 8.2. Note that with the newer IRIG Standard 200-04, two of the designations have changed:
the older B000 has become B004 and B120 has become B124.
Designation, New (Old) Signal Type Code Components
B004 (B000) Pulse width code, No carrier BCD
T OY
, BCD
Y EAR
, CF, SBS
B003 Pulse width code, No carrier BCD
T OY
, SBS
B124 (B120) Sine wave, amplitude modulated, 1 kHz BCD
T OY
, BCD
Y EAR
, CF, SBS
B123 Sine wave, amplitude modulated, 1 kHz BCD
T OY
, SBS
Table 8.2: IRIG-B Time Code Types Available
The IRIG-B time code consists of 100 bits produced every second, 74 bits of which contain
various time, date, time changes and time quality information of the time signal. Consisting of
logic ones, zeros and reference bits, the time code provides a reliable method of transmitting time
to synchronize a variety equipment.
Three functional groups of bits in the IRIG-B time code are arranged in the following order:
Binary Coded Decimal (BCD), Control Function (CF) and Straight Binary Seconds (SBS). The
BCD group, with IEEE 1344 OFF, contains only time information including the seconds, minutes,
hours and days, recycling yearly. With IEEE 1344 ON, BCD adds year information. The CF group
contains other information including time quality, leap year, pending leap seconds and parity.
Reference bits separate the various components of the IRIG-B time code.