HP 5384A Service Manual

HP 5384A and HP 5385A
Operation and Progr a mming
ope rated since be ing powered-up, the fr e quency
measurement is made using the last gate time se lected.
3-44.
PER key selects the period mode of operation
for the Channel A input. When the PER key is pressed,
the period of th e signal at input A is measured. The
measure ment is automatically made using the last
gate time selected. Th e gate time is displayed in the
right side of the LCD. As in frequency A, the reso-
1 uti on of the measu re ment is affected by the gate
time, since the HP 5384A/85A are reciprocal co unters.
3-45. Reciprocal
co unt ers use the gate time to
accumulate events !cycles of input signal) du ring the
length of the gate time. The gate time is di v ided by the
number of event s ( by the microcomputer ) to deter-
mine the average period of the signal. Th e longer the
gate time, the larger number of event s are accumu-
lated. An increased number of accumulated events
will increase the resolut ion of the measurement.
3-46.
XlO ATTN key provides attenuation of the in-
put signal on Channel A by a factor of approximately
20. Each press of the X20 ATTN key toggle s between
enabling and disabling an attenuation circ uit. When a
black arrow appears in the LCD above the "ATTN"
label, the signal is attenuated. When no arrow appears,
the signal is not attenuated.
3- 47 . The XlO ATTN sets the sensitivity of the Chan-
nel A input to either 10 mV rms or 200 mV rms range if
the MANUAL TRIG LEVEL A control ( di sc u ssed later)
is in midrange position or disabled. The X20 ATTN
operates
independently of the front panel key MAN
LEVEL. When the MAN LEVEL key is enabled, the X20
ATTN function will cau se the range of the MANUAL
TRIG LEVEL A control to incre ase approximately 20
times.
3-48. The
FILTER key provides a 100 kHz Low Pass
Filter that can be toggled into or out of the Channel A
signal path. The Low Pa ss Filter will attenuate fre-
quencies above 100kHz. When the FILTER is in the
sign al path, a black arro w will appe ar in the LCD
above
the label ''FILT".
3-49. The FILTER will impro ve the accuracy and
resolution of frequency measurements below 100
kHz by blocking high frequency signals and noise that
may be riding on the low frequency bein g measured.
3-50. B Channel and A&B
3-51. F igu re 3-3 shows the front panel B and A&B
funct io n keys. The F R EQ key selects th e frequency
3-4
rf:i;IJ' B ~~ ;
' '
I
'
.
•
'
. '
·- .. --
Figure 3-3. Front Panel 8 and A&B fun ction Keys
mode of operation for the B Channel input for display
on the LCD. Channel B frequency range for the HP
5384A is 50 MHz to 225 MHz. Channel B frequency
range for the HP 5385A is 90 MHz to 1000 MHz.
3-52. When channel B is selected, a black arrow
app ea rs in the bottom of the LCD over the " B" label
l ocated directly below the display window.
3-53. MAN LEVEL key enables or disabl es the front
panel MANUAL TRIG LEVEL A/ MAN UAL ATTN LEVEL
B co ntrol in the IN PUTS section.
3-54.
Wh en the MAN LEVEL control is enabled (on),
an
arrow will appear in the LCD above the MAN LVL
label. The trigger level of channel A b eco me s
manually variable and the attenuation ra nge becomes
manually adjustable in Channel B.
3-55. Wh en the MAN LEVEL control is di sabled (off),
the MANUAL TRIG L EV EL A/MANUAL ATTN LEVEL B
co ntr ol has no effect on input sensitivity of e ither
channel. Channel A sensitivity is maximum (<10 mY
rms) and Channel B se n si tiv ity is controlled by an
a
utom atic gain circuit for improved noise reject ion.
3-56. GATE and DISPLAY DIGITS
3-57. The GATE keys are shown in figure 3 -4. The
GATE keys select the approximate gate tim e in decade
ranges. The
actual gate time is determined by the
mi c ro co mputer .
3-58.
The 0.1 s, 1.0 s, and 10 s keys select gate times
from 0.1 second to 10 seco nd s for frequency, pe riod
and c he ck measurements.
3-59. The greater
the gate time the greater the
accuracy and the number of digits of resolution you
may ob tain.
0.1 s 3 to 8 digit s
1.0 s 3 to 9 digit s
10 s 3 to 10 d igits

HP 5384A Specifications

General

Brand	HP
Model	5384A
Category	Cash Counter
Language	English