Front Panel Operation
Publication 31231, Rev. J, October 2003
2-39
2.3.15
External Scan Amplitude Modulation (Opt. 29)
(Series 12500A/12700A Only)
Scan AM (Logarithmic AM)
Press
[AM]
to select the modulation parameter. Refer to the modulation parameters and specifications
in Chapter 1 for detailed information.
Using Scan Modulation
Scan AM is defined as a logarithmic change in the RF output level for a linear change in the input voltage.
Here the modulation is expressed in dB/volt. This modulation has a bandwidth of DC to 150 kHz. The carrier
power will decrease as the input voltage is increased. If the output voltage drops below 0 volts the signal may
be clipped. Scan AM is essentially an open loop function. To maintain output amplitude accuracy, the
operator should periodically ‘force’ a level re-calibration by exiting and re-enabling the modulation (Use the
“
Turn AM Off
” softkey).
Figure 2-23: Scan Modulation Selection
Scaling
When using the Scan AM mode, the scaling parameter determines how much modulation (attenuation) is
produced for each volt of input. Scaling can be changed from 0.0 to 65.0 dB/V using the Step keys, Knob or
Key Pad entry. Select Scan from the AMPLITUDE MODULATION screen, with the AM Mode: parameter
highlighted, by pressing the UP or DOWN Step key.
Example for Scan set-up:
a.) Set Frequency to 3 GHz and Power Level to +10 dBm; with Scaling (as above) at 10.0 dB/V;
Connect 1 VDC source to the AM Input BNC on the Front or Rear Panel; Connect power sensor to
the RF output connector on the 12000A; Turn RF ON by pressing the ONOFF key under OUTPUT
(The RF ON LED will turn on) and the power meter should read +10 dBm.
b.) To turn Scan ON; Press the softkey next to Turn AM On (Softkey now changes to Turn AM Off). The
power meter should read 0 dBm.
c.) To turn Scan OFF; Press
Turn AM Off
softkey.
d.) To modulate the RF Output: Connect a Sinewave, Triangle wave or Squarewave (Staying within the
Input Voltage of 0 V to +6 V per “Input Voltage”) to the AM Input BNC.
e.) To turn Scan OFF; Press
Turn AM Off
softkey.
f.)
To modulate the RF Output: Connect a Sinewave, Triangle wave or Squarewave (Staying within the
Input Voltage of 0 V to +6 V per “Input Voltage” on the next page) to the AM Input BNC.
NOTE:
With the Scaling set to 10.0 dB/V, the 1VDC input reduces the RF output by
–10 dB.
☛
Summary of Contents for Series 12000A
Page 3: ...DECLARATION OF CONFORMITY ...
Page 4: ......
Page 11: ...Preface Publication 31231 Rev J October 2003 vii ...
Page 14: ...Series 12000A Microwave Synthesizers x Publication 31231 Rev J October 2003 ...
Page 18: ...Series 12000A Microwave Synthesizers xiv Publication 31231 Rev J October 2003 ...
Page 20: ...Series 12000A Microwave Synthesizers xvi Publication 31231 Rev J October 2003 ...
Page 22: ...Series 12000A Microwave Synthesizers xviii Publication 31231 Rev J October 2003 ...
Page 24: ...Series 12000A Microwave Synthesizers xx Publication 31231 Rev J October 2003 ...
Page 62: ...Series 12000A Microwave Synthesizers 1 38 Publication 31231 Rev J October 2003 ...
Page 234: ...Series 12000A Microwave Synthesizers B 2 Publication 31231 Rev J October 2003 ...
