HP (Hewlett-Packard) HP 8568B TV Converter Box User Manual


 
9. 6
dB
Resolution
Bandwidth
Adjustments
Reference
Related Performance
Test
Description
Equipment
Procedure
IF-Display Section
A4A9
IF Control
6
dB
Resolution Bandwidth Accuracy Test
The CAL OUTPUT signal is connected to the RF INPUT. Each of the
adjustable resolution bandwidths is selected and adjusted for the
proper bandwidth.
No test equipment is required for this adjustment.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Position the instrument upright and remove the top cover.
Set the LINE switch to On, press (INSTR PRESET) and select
SIGNAL INPUT 1.
Connect CAL OUTPUT to SIGNAL INPUT 1.
Key in (CENTER FREQUENCY) 100 MHz, [FREQUENCY SPAN) 5 MHz
(-13
MHz, and
ILIN_).
Press [REFERENCE LEVEL) and adjust the DATA knob to place the
signal peak near the top CRT graticule. The signal should be
centered about the center line on the graticule.
Press PEAK SEARCH , MKR
+
a,
and MARKER (al.
Using the DATA knob, adjust the marker down one side of the
display signal to the 6
dB
point; CRT MKR A annotation indicates
.500
x
Adjust
A4A9R60
3 MHz for MKR In] indication of 1.5 MHz while
maintaining the marker at
.500
X using the DATA knob. Refer to
Figure 4-7 for the adjustment location.
Press MARKER
[nl.
Adjust the marker to the 6
dB
point on the
opposite side of the signal (CRT MKR A annotation indicates 1.00
X. There are now two markers; one on each side of the signal at
the 6 dB point.
CRT MKR A annotation now indicates the 6
dB
bandwidth of the 3
MHz bandwidth filter. The bandwidth should be 3.00 MHz
*0.60
MHz
Key in
(REsBW)
1 MHz,
CFREQUENCY
SPAN) 2 MHz, (PEAK SEARCH),
and
[MKR).
If necessary, readjust by pressing
PREFERENCE
LEVEL) and using the DATA knob to place the signal
peak near the top of the graticule.
Press MARKER
IOFF)
then MARKER
a.
4-24 Option 462