Check Trigger Bandwidth - Tektronix 7B70 Time Base Instruction Manual

Performance Check/Calibration-7B70 (SN 8205000 and Up)
Partial Procedure
If beginning a partial procedure with this step, set the
controls as given under Preliminary Control Settings except
a s follows:
-1-IMEJDIV 10 ms
e. Change the '7" connector from the low-frequency
generator to the Type 191 signal output connector (using a
GR to BlVC adapter). Set the Type 191 frequency to 20
MHz and adjust the amplitude for 125 millivolts.
f
.
CH EC K-Using the control settings in Table 5-2,
check for stable triggering and a lit TRIG'D lamp for each
condition listed (see step 12a).
12. Check Trigger Bandwidth
a. In the following portions of this step, adjust the 7B70
TIMEIDIV and LEVELISLOPE a s necessary t o provide 2 or
3 cycles of triggered waveform.
b. Set the controls a s given under Preliminary control
settings except as follows:
7B70 TIMEIDIV 10 ms
c. Connect a 200 Hz sine wave from the low-frequency
sine-wave generator through a "T" connector and coaxial
cable to the 7A16A input and from the other side of the
"T" connector through
a
coaxial cable and
a
2X attenuator
t o the EXT TRIG IN connector. Adjust the sine-wave
generator for a 0.5 division display on the CRT.
d. CH ECK-Using the control settings in Table 5-1,
check for stable triggering and a lit TRIG'D lamp for each
condition listed. Use the TIMEIDIV control as necessary
for optimum viewing of display.
TABLE 5-1
7870
1
Sine-Wave Generator
200 Hz 0.5 div
AC HF
REJ
200 Hz 0.5 div
- -
200 Hz 0.5 div
AC LF REJ
I NT
30 kHz 0.5 div
TABLE 5-2
AC HF REJ
- -
AC
- -
AC HF REJ
DC
AC LF REJ
ACHF REJ
g. Change the "T" connector from the Type 191 signal
generator to the 067-0532-01 Calibration Fixture output
connector. Set the Calibration Fixture frequency to 200
MHz and adjust the amplitude for a 1.5 division display.
I NT
EXT
E XT
E XT
E XT
,
EXT
h. CHECK-Using the control settings in Table 5-3,
check for stable triggering and a lit TRIG'D lamp for each
condition listed.
7 870
TABLE 5-3
COUPLING
DC
AC
AC LF REJ
- -
D C
AC
AC LF REJ
Type 191
50 kHz
200 Hz
200 Hz
200 Hz
30 kHz
50 kHz
SOURCE
EXT
E XT
EXT
INT
INT
INT
Frequency
20 MHz
20 MHz
20 MHz
20 MHz
20 MHz
20 MHz
0.5 div
125 mV
125 mV
125 mV
125 mV
125 mV
i.
Change the "T" connector from the 067-0532-01 cali-
bration fixture to the low frequency sine-wave generator
output connector. Adjust the sine-wave generator for a 0.3
division display of
a
30 Hz signal. Reset the TRIGGERING
MODE to NORM.
Amplitude
125 mV
125 mV
125 mV
0.
r
0.5 div
0.5 div
Scans
by ArtekMedia O 2006
7870
COLlPLlNG
AC
DC
-
AC LF REJ
AC
DC
AC LF REJ
Calibration Fixture
SOURCE
INT
INT
INT
EXT
1
EXT
EXT
Frequency
200 MHz
200MHz
p p
200 MHz
200 MHz
200 MHz
200 MHz
Amplitude
1.5 div
1.5 div
1.5 div
375 mV
375 mV
375 mV