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Table 4: Frequency Test Points
Frequency
30 MHz
50 MHz
100 MHz
170 MHz
6.4 Sine Out Amplitude Verification. Set the fre-
quency of the 409B to 10 MHz. Connect the 409B to
the oscilloscope set for 50Ω termination. Set the
oscilloscope to measure to amplitude using at least
16 averages. Verify a reading of 1Vpp
Repeat for the other outputs.
6.5 Level Command Test. Leave the output fre-
quency set to 10 MHz. Send the commands "Vn
512" to each channel, where "n" is your channel
number being tested. Verify that the amplitude on
each channel decreases by one-half. Send the "R"
command to reset the levels before performing the
next tests.
6.6 Output Flatness Verification. Verify that the
outputs are flat with frequency by performing the
following test: Connect the 409B to the oscilloscope
set for 50Ω termination. Use the same settings as
Sine Out Amplitude Verification. Note the voltage
reading.
6.7 Set the 409B to the values of Table 4. Verify that
the oscilloscope amplitude reading remains within
3dB (x1.414 to x0.707) of the value noted in the
±
previous paragraph. (limit upper frequency to150
MHz)
6.8 Repeat the output flatness verification test for
each output.
6.9 External Clock Input Verification. Set the fre-
quency output to 10.000 MHz by sending the com-
mand "F0
10.7374182" (scaled per section
4.0). Connect a 400 MHz external clock source via a
short coaxial cable to the external clock BNC on the
rear panel. Send the command "Kp 01". Send the
command "C e" to select the external clock input.
6.10 Verify an output of 10.0000000 MHz, ±1 Hz.
You must account for any frequency errors in your
external clock source.
NOVATECH INSTRUMENTS
6.11
default values by sending the "CLR" command.
Tolerance
45 Hz
1 LSD
±
±
6.12 This concludes the verification test of the
75 Hz
1 LSD
±
±
409B.
150 Hz
1 LSD
±
±
7.0
255 Hz
1 LSD
±
±
7.1 The 409B has two adjustable components: Y2,
frequency, and R22, output amplitude. Calibration
should be performed only if the 409B fails the per-
formance test or if the unit has been repaired. Rou-
0.25Vpp.
±
tine adjustments are not recommended nor generally
required. This procedure assumes that the 409B has
failed the performance test or has been repaired.
Calibration of the Model 409B requires that the case
be opened. Calibration should be performed only by
7.2 Access to the adjustments is provided by remov-
ing the rear panel fasteners. Remove the two phillips
head screws on the rear panel, the power receptacle
nut, and the two jack-screws holding the RS232 con-
nector. Tip the rear panel away from the instrument
and slide the top cover off. Be careful not to unduly
flex the connecting wires.
7.3 The adjustments shown are set to 1/2 the speci-
fication values.
If your unit has the /R option installed, the oscillator
7.4 Frequency Adjust, Y2. Set the output of the
409B to 10.0000000 MHz using the command "F0
10.0000000". Connect output of channel 0 to
your frequency counter set for 50 Ω termination.
9
Return the 409B to normal operation and
CALIBRATION
WARNING:
qualified personnel. The internal components are
static sensitive.
NOTE:
Allow the 409B to warm up for at least 15 minutes
before performing any adjustments. For optimum
performance the 409B should be calibrated in an
environment similar to its installation.
NOTE:
adjustment is the same, except the location has
moved to the adapter board.
409B Manual, 17-Apr-2015
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