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13
2.2.4.2.
Amplitude-modulated
(AMI HF-signal generator
Internal
- Preliminary adjustment according to chap. 2.2.4. 1..
- Press button AM/1 kHz. The HF·signal is modulated in amplitude by 30 % at an internal frequency of
1
kHz.
- For indications on checking and adjusting, see the individual checking and adjusting procedures for the
object to be measured or chapter
2.3 ..
External
- Preliminary adjustment according to chap. 2.2.4.1 ..
- Press button AM/EXT.
- Supply the modulation voltage to connector LF IN; maximum 16 V peak-peak, maximum d.c. level ±12 V.
- External modulation frequency 20 Hz ... 20 kHz.
- Adjust the modulation depth by the amplitude of the modulation voltage; voltage necessary 0.2
V /10
%
amp Iitude·modulation.
2.2.4.3. Frequencv-modulated
(FM) HF·signal generator
Internal
- Press buttons 75 · 110 or 10.3 · 11.1 MHz.
The selected range scale is indicated by a LEO.
- Set the pointer at the required frequency by potentiometer
F REOUENCY.
Not marked frequency values should be interpolated between two marks.
- It necessary, calibrate the frequency at the nearest calibratlon-rnark according to sub-para 2.2.4.5 ..
- Press button FM/1 kHz; the HF-signal
is
modulated in frequency by 1 kHz and a frequency sweep of about
25 kHz.
- Apply the signal, available at BNC connector HF OUT, across a cable to the object to be measured.
Isse accessories, chapter 1.3.).
- Adjust the required output voltage by means of potentiometer
HF
AMPLITUDE.
Note
When using harmonics the frequency sweep is multiplied by ~he order-number of the harmonics.
External
- Preliminary adjustment according to chap. 2.2.4.3 ..
- Press button FM/EXT.
- Supply the modulation voltage to BNC connector LF IN; maximum input voltage 70 V peakpeak.
- Adjust the external modulation frequency; 20 Hz ... 60 kHz.
- Adjust the modulation sweep with the external voltage; necessary voltage 0.2 V/7.5 kHz sweep (maximum
sweep 75 kHz).
- If necessary, supply a multiplex-signal to BNC connector LF IN
2.2.4.4. Wobble generator
- Pressrange·button
75 ... 110 or 10.3 ... 11.1 MHz.
The selected range-scale is indicated by a LED.
- Set the pointer to the required frequency by potentiometer
FREQUENCY.
Not marked frequency values should be interpolated.
- Press button WOB.
- Connect BNC-connector 1 kHz/SWEEP OUT to the X·input of an oscilloscope.
- Adjust the X-amplitude of the oscilloscope.
- Apply the wobbulated signal across a cable to the object to be tested.
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