Symmetricom 58503B, Руководство по началу работы, Страница: 77 / 90

Chapter 4 58503B Specifications
Specifications and Characteristics
Getting Started Guide 4-3
10 MHz Output
Specifications
Locked:
Frequency Accuracy: Better than
1 × 10
−
12
, for a one-day average,
0° C to 50° C.
Unlocked:
Holdover aging:
<1 × 10
−
10
per day average
frequency change in 24 hours of
unlocked operation. (See Note 1.)
Phase Noise: (Locked)
Time Domain Stability: (Locked)
(See graph on next page.)
Supplemental Information
• Waveform: Sine wave
• Amplitude: >1 volt p-p into a
50
Ω
load
• Harmonic Distortion:
<
−
25 dBc (Typical)
• Non-harmonic signals:
<
−
60 dBc (Typical)
• Source impedance:
50
Ω
(nominal)
• Coupling: ac
• Connector: BNC
Note 1
This specification has a 95% probability,
and is based on the availability of four or
more GPS satellites during three days of
locked operation with a fixed antenna
location. The temperature must remain
within a 10
°
C range between 10
°
C and
40
°
C.
Note 2
When a quartz crystal oscillator has not
been operated for a period of time, or if it
has been subjected to severe thermal or
mechanical shock, as might be
encountered during product shipment, the
oscillator may take some time to stabilize.
In most cases, the oscillator will drift and
then stabilize at or below its specified rate
within a few days after being turned on.
In isolated cases, depending upon the
amount of time the oscillator has been off
and the environmental conditions it has
experienced, the oscillator may take up to
one week to reach its specified aging rate
and to operate without significant
frequency “jumps.”
When a Hewlett-Packard GPS Receiver
is initially turned on and locked to the
GPS satellite system, it will achieve GPS
lock within 30 minutes of operation. It has
a 95% probability of meeting unlocked
(holdover) specifications after 24 hours of
warmup, followed by GPS locked for
48 hours. The longer GPS Receiver (and
its quartz oscillator) operates, the better
its stability and unlocked (holdover)
performance becomes.
1 PPS Output
Specifications
Locked:
Jitter of leading edge: <750 ps
rms with at least one satellite in
view, SA on.
Time Accuracy:
<110 ns with respect to UTC
(USNO MC)—95% probability
when unit is properly installed,
calibrated, and locked to GPS.
Unlocked:
Accumulated time error: <8.6
µ
s
accumulated in 24 hours of
unlocked operation. (See Note 1.)
Supplemental Information
• Pulse Width: 26
µ
sec
• Amplitude: >2.4 volts into
50
Ω
load. (TTL compatible)
• Connector: BNC
• Rise time: <25 ns
Additional Features
Alarm Output: TTL open collector
with internal pull-up resistor.
Circuit can sink up to 10 ma.
Provides a logic output to allow
monitoring of normal (H) and
abnormal (L) operation
externally and remotely.
BNC connector.
Front Panel Indicators (LEDs):
Power
GPS Lock
Holdover Mode
Alarm
Remote Interface:
RS-232-C DTE configuration:
Complete remote control and
interrogation of all instrument
functions and parameters.
Factory defaults: baud rate 9600,
8 data bits, 1 start bit, 1 stop bit,
no parity. Other settings are
programmable.
Connector: 25-pin female
rectangular D subminiature on
rear panel.
Time code output is available to a
computer immediately preceding
the 1 PPS signal for the current
second.
Environmental
Specifications
Time and Frequency Reference
Receiver (58503B)
Operating: 0° C to +50° C
Storage:
−
40° C to +80° C
Antenna (58532A)
Operating:
−
30° C to +80° C
Storage:
−
40° C to +85° C
Offset From
Signal (Hz) SSB Phase
Noise (dBc)
1
−
85
10
−
125
100
−
135
1000
−
140
10000
−
145
Averaging
Time Seconds Root Allan
Variance
0.01
1.5 × 10
−
10
0.1
1.5 × 10
−
11
1
5 × 10
−
12
10
5 × 10
−
12
100
5 × 10
−
11
1000
5 × 10
−
11