TB 9-6625-2340-24
(14) Press MARKER
key and position moveable marker 60 dB down from the
stationary marker on the positive slope of the signal trace.
key and position moveable marker 60 dB down from the
(15) Press MARKER
stationary marker on the negative slope of the signal trace. Record displayed indication in
Actual Indication column of table 8.
(16) Using the actual indication for 60 dB (table 8) at 3 MHz resolution bandwidth
setting and the actual indication for 3 dB (table 7) at 3 MHz resolution bandwidth setting,
calculate the bandwidth selectivity by using the formula below. If calculated ratio is not
within limits specified in first row of table 8, perform b below.
60 dB reading
3 db reading = ratio
(17) Repeat the technique of (12) (d),(e), and (f) and (13) through (16) above for
If calculated ratios are not within limits specified in table 8, perform b below.
Table 8. 60 dB Bandwidth Accuracy
Test instrument
FREQUENCY
Calculated
RES BW
SPAN
VIDEO BW
Actual
ratio
key
key
key
indication
Max
3 MHz
25 MHz
100 Hz
15:1
1
MHz
15 MHz
300 Hz
15:1
300 kHz
5 MHz
AUTO
15:1
100 kHz
2 MHz
AUTO
15:1
30 kHz
500 kHz
AUTO
13:1
10 kHz
200 kHz
AUTO
13:1
3 kHz
50 kHz
AUTO
11:1
1 kHz
10 kHz
AUTO
11:1
300 Hz
5 kHz
AUTO
11:1
100 Hz
2 kHz
AUTO
11:1
30 Hz
500 Hz
AUTO
11:1
10 Hz
200 Hz
AUTO
60 dB points
separated by <100 Hz
b. Adjustments
(1) Remove top cover from TI.
(2) Press TI keys as listed in (a) through (i) below:
2-22 GHz.
(a)
CENTER FREQUENCY, 100, MHz.
(b)
FREQUENCY SPAN, 5, MHz.
(c)
RES BW, 3, MHz.
(d)
REFERENCE LEVEL, 10, dBm.
(e)
SCALE LIN.
(f)
SHIFT.
(g)
AUTOA.
(h)
REFERENCE LEVEL.
(i)
(3) Adjust DATA knob to position trace at (or just below) reference level (top)
graticule line.
18