HP 5065A Operating And Service Manual page 37

Model 5065A
Circuit Diagrams, Theory, and Maintenance
Table 5-2. In-Cabinet Performance Check (Cont'd)
Figure 5-3. Harmonic and Non-Harmonic
Distortion Test Setup
SPECTRUM
ANALYZER
8552B/8553B
5 0 n FEEDTHRU
5MHz IMHz 100kHz
HP5065A
To perform the check proceed as follows:
a. Connect 5 MHz output through 50-ohm Feed-
thru to Spectrum Analyzer input. Check spectrum at
5 MHz center to 4th harmonic (20 MHz). Harmonics
should be below 40 dB.
b. Remove connection from instrument 5 MHz
output and connect to 1 MHz output jack. Check
spectrum at 1 MHz center to 5th harmonic (5 MHz).
Harmonics should be below 40 dB.
c. Remove connection from instrument 1 MHz
output and connect to 100 kHz output jack. Check
spectrum at 100 kHz center to 50th harmonic
(5 MHz). Harmonics should be below 40 dB. Dis­
connect Spectrum Analyzer from instrument.
5. NON-HARMONIC DISTORTION CHECK
Non-harmonic distortion in the 5 MHz, 1 MHz, and
100 kHz output signals should be at least 80 dB
down from the 1 Vrms output. To perform this
check, a Spectrum Analyzer is tuned to the funda­
mental frequency and an amplitude reference is
established. The output frequency spectrum is then
investigated to determine fundamental-to-sideband
amplitude relationship at non-harmonic points in
the spectrum.
Set instrument to normal operation mode (CON­
TINUOUS OPERATION light on).
Connect equipment shown in Figure 5-3.
To perform the check proceed as follows:
a. Connect 5 MHz output through 50-ohm Feed-
thru to Spectrum Analyzer input. Check spectrum at
5 MHz ±5 kHz. All sidebands should be at least 80 dB
below the carrier.
b. Remove connection from instrument 5 MHz
output and connect to 1 MHz output jack. Check
spectrum at 1 MHz center ±5 kHz. All sidebands
should be 80 dB below the carrier.
c. Remove connection from instrument 1 MHz
output and connect to 100 kHz output jack. Check
spectrum at 100 kHz ±5 kHz. All sidebands, except
harmonically related, should be 80 dB below the
carrier. Disconnect equiment from instrument.
6. CLOCK PULSE CHECK (OPTION 001 and 003)
a. Pulse Parameters. Connect 5065A1 PPS out­
put to Oscilloscope vertical input. Set instrument for
normal operation (CONTINUOUS OPERATION
light on, ALARM light off, DIVIDER MODE switch
to AUTO START). Parameters should be as
indicated:
Rate: 1 pulse-per second
Amplitude: +10V peak ±10%
Width: 20 ^sec minimum
Rise Time: <50 nsec
Fall Time: <2 /^sec
b. Pulse Jitter. To verify pulse jitter specifica­
tion (<5 nS rms pulse to pulse) one of two methods
may be used. If the HP Model 5390A system is to be
used for checking short term frequency stability,
use the procedure described in Method 1 below. If
the 5390A system is not available, use the proce­
dure described in Method 2.
Method 1.
In this procedure the Model 9825A Computing Con­
troller is used to control the Model 5345A frequency
counter. The counter takes data under the diretion
of the Controller. The Controller performs the RMS
calculation. Proceed as follows:
(1) Set 5345A front panel controls as
SAMPLE RATE CCW
FUNCTION . . . TIME INT. A TO B
GATE TIME MIN
CHANNEL A and B
Input Resistance 1MH
ATTEN X20
Coupling DC
SLOPE +
Input COM A
(2) If a cable is connected to Channel B
input remove it.
(3) Connect 1 PPS output from 5065A
50 ohm feedthrough termination to the
Channel A input of the 5345A. Adjust Chan­
nel A and B LEVEL controls so that each
channel triggers about in the middle of the
pulse (+5V) and the counter displays ap­
proximately 1 second.
5-3