16
- Set the band-pass curve at the middle of the picture with potentiometer FREQUENCY.
- Adjust the height of the band-pass curve with potentiometer HF AMPL ITUDE.
- Adjust the width of the ba nd-pass curve with potentiometer SWEEP W IDTH.
-
Check the band-pass curve; if necessary, correct it. Th e effect of an adjustment can
be determined
immediately on the ba nd-pass curve.
Note
When using harmonics the frequency sweep is multiplied by the order number of the h armonics.
Determining ,he band width
Sy defined shifting in the h orizontal direction the band width (at
70
%
of the h eight of the picture) can be
determined as follows:
- Position the point of intersection, e.g. of the right edge of the band-pass curve and a fictitions h orizontal
line at 70
%
of the height of the curve on a prominent point on the graticule by means of potentiometer
FREQUENCY.
- Read the frequency at the scale and note the value.
- S hift the band-pass curve horizontally with potentiometer FREQUENCY so that the second edge is
positioned at the same fictitions point of intersection (at
70
%
of the height of the picture) as in the first
adjustment.
- Read the frequency; the difference between the two frequencies is the band width.
Note
Use a d.c. indicator (oscilloscope or meter) so that the base line is horizontal and undistorted at a large
wobbulati ng-sweep.
2. 2.4.5. Calibration
The calibration points are indicated on the scale by the symbol
Y
or}. . A moving coil meter, which is
illuminated at calibration mode, serves as indicator.
Checking
If a very accurate HF-signal, e.g. of 21.5 MHz is needed, this can be checked as follows:
-
Switch on the instrument and wait at least
30
minutes for it to warm up.
- Depress range-button
10
-
30 M Hz; the diode alongside the top scale will light up.
-
Depress button CA L.; the indicator will light up. If necessary, unlock button
was
..
- Set the scale pointer to that calibration mar k
( Y
at mark .2) wh ich is nearest to the nominal value of 21.5 MHz.
- Set the scale pointer exactly on the minimum which lies between two full-scale deflections of the indicator.
- Check, that the line of the scale pointer corresponds to the calibration mark.
Calibration
If the line of the scale pointer is not exactly over the calibration m ark calibrate as follows:
- Set the scale pointer exactly on the calibration mark.
- Hold the largest knob of control FREQUENCY with one hand.
- Adjust the smaller knob - against the resistance of the slipping clutch - to obtain the required minimum
(zero beat) between two maxima.
- Release the large button.
- Adjust for exact zero beat.
- Check that the line of the scale pointer corresponds to the calibration m ark. Repeat the calibration procedure,
if necessary.
2.2.4.6. 1 kHz-Generator
- Release all push-buttons, especially button
was.
- The 1 k Hz-signal, with an amplitude of 2 Vr.m.s
.•
is availi)ble at SNC-connector 1 k Hz/SWEEP OUT.
Содержание PM5324
Страница 1: ...HF Generator 100kHz 110MHz PM5324 9452 053 240 1 9499 450 05511 730801 1 01 ...
Страница 15: ...14 Fig 4 Front view Fig 5 Rear view ...
Страница 43: ...Fig 33 Front view with item numbers Fig 34 Bottom view ...
Страница 44: ...44 Fig 35 Top view Fig 36 Left side view ...
Страница 45: ...45 0 0 0 0 1 ji I I MAB225 Fig 37 Scale dri ve n ...
