Symmetricom ET6000, User Manual

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GENERAL INFORMATION
1.4.3 ACCURACY
The accuracy of the pulse rates listed in Section 1.4.2H is the same as that in Section 1.4.1A.
1.4.4 TIMING INPUTS
A. J10 - 1PPS INPUT (TIME INTERVAL MEASUREMENT) or
EXTERNAL FREQUENCY MEASUREMENT or
SINGLE EVENT LOG
TIME INTERVAL MEASUREMENT
Used to measure the time interval between the internally generated GPS 1PPS and an
external 1PPS input. The resolution of this measurement is 1 nanosecond with
accuracy better than 10 nanoseconds. At power-up, this feature is DISABLED. If
enabled, the measurement is displayed on the Second Menu Screen. Refer to
Chapter Three. Also see paragraphs entitled, “Enable Time Interval,” “Disable Time
Interval,” and “Request Time Interval,” in Chapter Four of this User’s Guide.
EXTERNAL FREQUENCY MEASUREMENT (MODELS ET6000 AND
ET6010 ONLY)
Frequency Range
1Hz to 10MHz (discrete, whole numbers - not fractional parts).
Input Wave Form From 1Hz to 10MHz
Rectangular or square wave (minimum pulse width fifty nanoseconds).
Amplitude Range:
Logic “0” +0.2V
±
0.2VDC
Logic “1” +2.4V to +15VDC
Input Wave Form From 100KHz to 10MHz
Sinusoidal Amplitude Range: 1 - 5 volts peak-to-peak
SINGLE EVENT LOG
This option provides the capability of logging the time occurrences of up to 256
events from one input. A pulse on the event input will cause the time to be
logged/stored on either the rising (positive going) or falling (negative-going) edge of
the input pulse. The edge designated as on time is programmable via the front panel
keyboard or remotely via the RS-232 I/O. Each event will have a defining number
from zero to 255 and the channel identifier.
Symmetricom Inc ET6xxx ExacTime GPS TC & FG (Rev C) 1-7