
TM 9-6625-474-14&P-3
and U1621D to pin 1 of U1520 (schematic 7), telling the
decade counting units to latch the accumulated count.
During the time that the GATE light and Load pulses
were being generated, the ramp voltage on the emitter of
Q1300 (a unijunction transistor) has been rising. Eventual-
ly, it will reach the voltage level necessary to turn on
Q1300. When Q1300 turns on, C1400 discharges and a
positive pulse of small duration is produced on pin 3 of
UU1422A. The falling edge of that pulse triggers both
U1421A and U1421B, generating two pulses (Reset and
Clear).
The Reset pulse generated by U1421A and U1420B will
be of shorter duration than the Clear pulse generated by
U1421B and U1420C. The pulse on pin 4 of U1420B resets
the U1520 internal decade counters (schematic 7). The
pulse on pin 10 of U1420C resets all other ECL circuits and
everything else. The CLR (Clear) pulse is of sufficient
duration to allow for the setup times, minimum reset times,
and a delay after reset before U1520 is ready to accept the
next Count Input. After the CLR pulse terminates, the
counter circuits are armed and ready to accumulate
another count.
Transistor Q1700 and associated components com-
prise the power on reset circuit. At power on, Q1700
conducts and stays on for a time interval determined by
the time constant value for R1700 and C1701.
Decade Accumulators
The 1st DCU circuit is located on schematic 4, the 2nd
DCU on schematic 7. The Measurement Gate is applied to
pins 7 and 6 of the first flip-flop, U1221, while the Count
Input clocks U1221 on pin 9 for a divide by two operation.
The remaining flip-flops, U1120, U1121B, U1121A, and
the feedback circuit through U1220B provides a divide by
five operation.
The entire circuit on schematic 4 is a divide by ten
decade accumulator with a bcd output code. The outputs
of the flip-flops are translated from ECL levels to TTL
levels by their associated buffer (amplifier) circuits,
U122A, Q1133 and Q1132, U1122B, and U1122C. The
3.7 V reference for U1122A, B, and C is set by the voltage
divider circuit, R1037 and R1036.
pins 12 and 1 of U1620 are hardwired, the 2nd DCU also
divides by ten.
When the reset signal on pin 2 of U1620 goes high, all
four outputs are set low and U1620 counts the negative
edges that occur on pin 14. At the end of every 100 counts
all of the binary inputs to U1520 should be low. Resistors
R1624, R1623, R1622, and R1715 operate as pull up
resistors to ensure that the D2 inputs for U1520 reach the
4.0 V level required for a logical “1” value.
6-Decade Ripple Through Counter
The 6-Decade Ripple Through Counter, U1520, in-
crements on the negative edge of an internal clock, All six
decades are reset to zero when the reset signal (pin 22) is
held low for at least 4
An internal overflow flip-flop (pin
12) is reset at thesametime. Reset must go high before the
next valid count can be latched.
Eight decade latches are provided internally, two for
storing the count from the 1st and 2nd DCU’S and six for
internal counter output. All latches are loaded when pin 21
goes low for at least 4
Ripple through time is about
12
The internal scan counter is driven by an internal
oscillator whose frequency is determined by C1511 (pins
39 and 40). The counter scans from the most significant
digit (MSD, pin 2) to the least significant digit (LSD, pin 9).
Pins 2 through 9 are the digit strobe outputs (time slot lines
TS1 through TS8).
A high level on the decimal point input (pin 10) resets a
blanking flip-flop output (pin 11), causing the display to
unblank. Pin 10 is brought high at the start of the digit
strobe time slot that has the active decimal point.
An overflow flip-flop (pin 12) is set on the first negative
transition occuring on the overflow input (pin 13). The
most significant bit (MSB) output from the eighth decade
(Pin 14) is used as overflow input.
Leading zero suppression is also provided internall y. At
the start of each scan counter cycle (MSD to LSD), the
display is blanked (pin 11 is low) until a non zero digit or
active decimal point is encountered. The display unblanks
during LSD (TS8) time or whenever the overflow output
(pin 12) is high.
The four translated voltage levels out of the 1st DCU go
Data output from U1520 appears on pins 20, 19, 18, and
to the first latch inputs of the 6-Decade Counter, U1520
17, in a multiplexed bcd format. The internal scan counter
(schematic 7), with the fourth bit value driving the 2nd
causes the proper decade count to appear on these lines at
DCU circuit, U1620 and associated components. Since
the same time as its corresponding digit strobe (time slot)
Содержание DC503a
Страница 1: ...e x _ 1 v w W i L ...
Страница 16: ...DC 503A DC 503A Universal Counter Timer REV A FEB 1981 XIV ...
Страница 27: ...Fig 2 2 Controls and connectors Operating Instructions DC 503A 2977 fli English 2 3 ...
Страница 39: ...Fig 2 2 Commandes et prises Instructions d utilisation DC 503A French 2 3 ...
Страница 51: ...Abb 2 2 Bedienungselemente and Anschliisse Bedienungsanleitung DC 503A German 2 3 ...
Страница 63: ...Fig 2 2 Controls and connectors Operating Instructions DC 503A 2971 01 Japanese 2 3 ...
Страница 125: ...Fig 8 2 Auxiliary Board A12 Assy ADJUSTMENT LOCA 2971 1 6 ...
Страница 169: ...SEE END OF MPL FOR WIRE ASSEMBLIES O1 0 pG C 0 DC 503A ...
Страница 186: ...0 2 TM 9 6625 474 14 P 3 Fig 0 1 DC 503A Universal Counter Timer ...
Страница 188: ...Table 1 1 1 2 TM 9 6625 474 14 P 3 ...
Страница 189: ...Table 1 1 1 3 TM 9 6625 474 14 P 3 ...
Страница 190: ...Table 1 1 1 4 TM 9 6625 474 14 P 3 ...
Страница 191: ...Table 1 1 1 5 TM 9 6625 474 14 P 3 ...
Страница 192: ...1 6 Table 1 1 TM 9 6625 474 14 P 3 ...
Страница 193: ...Table 1 1 1 7 Table 1 2 Table 1 3 TM 9 6625 474 14 P 3 ...
Страница 194: ...Table 1 3 Table 1 4 1 8 TM 9 6625 474 14 P 3 ...
Страница 197: ...2 3 TM 9 6625 474 14 P 3 Fig 2 2 Controls and connectors ...
Страница 211: ...3 5 Fig 3 1 TM 9 6625 474 14 P 3 ...
Страница 219: ...4 2 TM 9 6625 474 14 P 3 Table 4 1 LIST OF TEST EQUIPMENT REQUIREMENTS ...
Страница 240: ...5 7 TM 9 6625 474 14 P 3 Fig 5 9 Rear interface connector assignments ...
Страница 256: ...8 3 8 4 blank TM 9 6625 474 14 P 3 ...
Страница 257: ...8 5 8 6 blank TM 9 6625 474 14 P 3 ...
Страница 258: ...Fig 8 2 Fig 8 1 8 7 8 8 blank TM 9 6625 474 14 P 3 ADJUSTMENT LOCATIONS ...
Страница 259: ...8 9 8 10 blank TM 9 6625 474 14 P 3 PARTS LOCATION GRID Table 8 1 COMPONENT REFERENCE CHART See Fig 8 3 ...
Страница 260: ...TM 9 6625 474 14 P 3 8 11 8 12 blank ...
Страница 261: ...Fig 8 4 8 13 8 14 blank TM 9 6625 474 14 P 3 Table 8 2 COMPONENT REFERENCE CHART See Fig 8 4 PARTS LOCATION GRID ...
Страница 262: ...TM 9 6625 474 14 P 3 8 15 8 16 blank ...
Страница 263: ...8 17 8 18 blank TM 9 6625 474 14 P 3 Table 8 3 COMPONENT REFERENCE CHART See Fig 8 3 ...
Страница 264: ...8 19 8 20 blank TM 9 6625 474 14 P 3 ...
Страница 265: ...8 21 8 22 blank TM 9 6625 474 14 P 3 Table 8 4 COMPONENT REFERENCE CHART See Fig 8 3 ...
Страница 266: ...8 23 8 24 blank TM 9 6625 474 14 P 3 ...
Страница 267: ...8 25 8 26 blank TM 9 6625 474 14 P 3 DC 503A Table 8 5 COMPONENT REFERENCE CHART See Fig 8 4 ...
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Страница 269: ...8 29 8 30 blank TM 9 6625 474 14 P 3 DC 503A Table 8 6 COMPONENT REFERENCE CHART See Fig 8 3 ...
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Страница 271: ...8 33 8 34 blank TM 9 6625 474 14 P 3 DC 503A Table 8 7 COMPONENT REFERENCE CHART See Fig 8 4 ...
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Страница 273: ...Fig 8 5 8 37 8 38 blank DC 503A TM 9 6625 474 14 P 3 PARTS LOCATION GRID Table 8 8 COMPONENT REFERENCE CHART ...
Страница 274: ...8 39 8 40 blank TM 9 6625 474 14 P 3 ...
Страница 275: ...8 41 8 42 blank TM 9 6625 474 14 P 3 DC 503A Table 8 9 COMPONENT REFERENCE CHART See Fig 8 3 ...
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Страница 277: ...8 45 8 46 blank TM 9 6625 474 14 P 3 DC 503A Table 8 10 COMPONENT REFERENCE CHART See Fig 8 4 ...
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Страница 291: ...D 1 TM 9 6625 474 14 P 3 APPENDIX D MANUAL CHANGE INFORMATION ...
Страница 292: ...D 2 TM 9 6625 474 14 P 3 ...
Страница 293: ...D 3 TM 9 6625 474 14 P 3 P a g e 1 o f 2 ...
Страница 294: ...Page 2 D 4 TM 9 6625 474 14 P 3 ...
Страница 296: ...D 6 TM 9 6625 474 14 P 3 ...
Страница 298: ......
Страница 299: ...THE METRIC SYSTEM AND EQUIVALENTS ...
Страница 300: ...PIN 056816 000 ...