Frequency Display - Philips Pm 5326 Bedienungsanleitung

4.1.4
Frequency display
The circuitry comprises counter and display unit 2 and time base
unit
3.
The signal from the RF generator unit 1 is fed via connection
37
of
unit 6, Schmitt trigger
353,
pre-scale stage
358
and pin 37/~6 to the
counter input 352.12.
The reference frequency for the time base is generated by the X-tal
oscillator in combination with transistor 301.
The 4.000000
MHz
represent the basis wave in parallel resonant circuitry.
Via amplifier 302 the signal is applied to a divider chain. The first
stage
351
serves for division of 1:8, but, if necessary, for quicker
and slower reading of the display, the division can be altered to
1:4
or 1:16 (flickering of the last digit). Compensating this, the counter
input has either to be applied to
P
or
Q of unit 6. The subsequent
integrated circuits 352-355 are switched in for 1 :
lo4
division.
At
solder
joint U
-
suitable for failure chasing
-
50
Hz
(20 ms) can be measured.
Stages 356-358,
361
divide this frequency due to the chosen range in
l(10)-2-5 ratio. The signal, gated by
358,
is applied to the D-flip-flop
359,
generating the ~ / 2 gate time for the counter decoder driver 352,
unit 2.
Overmore it is applied to double monostable multivibrator
360,
which
generates the store- and reset pulses, determined by the RC combinations
605/514
and 609/516.
The timing diagram of the mentioned signals is shown in the figure
4.1-6.
If you have the COUNTER EXTernal mode, the frequency is fed via a
limiter stage, impedance transformer
303,
amplifier
304
to Schmitt-trigger
353.9. In this mode, trigger
353.6
is disabled.
Solder joints
A1-A3
are taken into account, if you have the
PM
5326X
version of 1 0 0
MHz
extended counter facility,
see Fig. 1 8 and SGS
17.
C O U N T E R
E X T
1
...
. 2 5 M H z
25
..
. 5 M H z
5
...
1 M H z
1 2 5 M H z
2 . 5
...
5 M H z
5
.
1 0 M H z
10
..
25 M H z
2 6
..
5 0 M H z
50
..
125 M H z
--
<
.1
...
>
.25 M H z
<
.25
...
>
,625 M H z
<
. 5
...
>
1.25 M H z
< 1
..>
2 5 M H z
< 2 5
..>
6 2 5 M H z
< 5 . > 1 2 . 5 M H z
<lo
..>
2 5 M H z
+5
...
>
6 2 . 5 M H z
6 0 . . A 2 5 M H z
--
D8rpiay format
--
.1
..
.25 M H z
.25
..
,625 M H z
. 5
..
1.25 M H z
. 5
...
1.25 M H z
.5
.
1.25 M H z
. 5 1 2 5 M H z
. 5
..
1.25 M H z
. 5
...
1.25 M H z
. 5
...
1.25 M H z
--
.1
...
.25 M H z
.25
..
.5 M H z
.5 . 1 M H z
.5 1 . 2 5 M H z
.5
..
1 M H z
5 1 M H z
. 5
...
1.25 M H z
5
...
1 M H z
5
...
1.25 M H z
Pin 363.1
Signal available at
--
0 5
...
,125 M H z
,125
...
.25 M H z
.25
.
.5 M H z
2 5
.
6 2 5 M H z
25
..
5 M H z
.25
. .
5 MHz
.25
..
,625 M H z
.25
...
.5 M H z
.25
...
,625 M H z
Pin 352.13
RF OUT connector
Pin 363.3
2 0 0 rnr.
200 mr
200 mr
20 mc
do mr
l o o m s
2 0 m l
4 0 rnr
100 mr
20
m3
G a t e t i m e icount enable1
Pin 352.12
X X X . X X kHz.
X X X . X X kHz
X X X . X X *HI
X . X X X X M H z
X . X X X X M H z
X . X X X X M H z
X X X X X M H z
X X . X X X M H z
X X . X X X M H z
X X X . X X M H z
Norntnal frequency range
PM 5326 X : 100 ms; X X . X X X MHz rerp.
Mearur~ng frequency range
Frequency range at inputs of the phase comparator
13631U 1
I
Fig. 4 . 1 - 5 Table of frequency ranges, gate times, display formats
Frsquency range a t
counter
lnput
13521U2)
Store
counter
Inlormation
1 1
Transfer
counter
lnformatlan
Normal operation
14
Counter reset