Theory of Operation— 2230 Service
Q202 and Q203 through R202 and R203 to return the out
put of the Delay Line Driver to an average dc voltage of
zero.
Delay Line DL9210 adds about 90 ns of delay to the
vertical signal. In that time, the Sweep Generator has
sufficient time to start producing a sweep before the verti
cal signal that triggered the sweep reaches the crt. This
permits viewing the leading edge of the triggering signal.
B andw idth L im it
BW LIMIT switch S226, C228, C229, and the diode
bridge formed by CR226, CR227, CR228, and CR229
reduce the bandwidth of the amplifier when desired. With
full 100 MHz bandwidth, R226 is grounded through BW
LIMIT switch S226, and the nonconducting diode bridge
isolates C228 and C229 from the vertical signal. With lim
ited bandwidth on, R226 is connected to the +8.6 V sup
ply, and the diode bridge is forward biased. The two
bandwidth limiting capacitors are then in the vertical signal
path, and high-frequency signals (above about 20 MHz)
are attenuated.
V ertical O u tp u t A m p lifie r
The Vertical Output Amplifier drives the vertical
deflection plates of the crt. Signals from the Delay Line go
to a differential amplifier formed by Q230 and Q231 with
tow- and high-frequency compensation provided by the RC
networks between the emitters. Thermal compensation is
provided by thermistor RT236, and overall circuit gain is
set by R233. The output stage of the Amplifier is two
totem-pole transistor pairs, Q254-Q256 and Q255-Q257,
that convert the collector currents of Q230 and Q231 to
proportional output voltages. Resistors R256, R258, R257,
and R259 are feedback elements and bias voltage divid
ers. Biasing is set so each transistor in a pair develops
one-half the final output voltage on a side. The amplifier
output signals drive the Vertical crt deflection plates.
Beam Find is used to keep the vertical trace within the
graticule area for locating off-screen and over-scanned
traces. When the front-panel BEAM FIND switch opens
the contacts of S390 (found on Diagram 9), the direct
-8 .6 V supply to R261 is removed, and emitter current
goes through R261 and R262 in series. The added series
resistance reduces the amount of available emitter current
and limits the amplifier’s dynamic range. In normal
amplifier operation, S390 connects the —8.6 V supply
directly to R261, and full emitter current is possible in the
output transistors.
A /B S weep S e p a ra tio n C irc u it
The circuit formed by Q283, Q284, Q285, and associ
ated components acts to vertically position the Nonstore B
trace with respect to the Nonstore A trace in BOTH Hor
izontal mode. In the B Sweep interval, the SEP signal from
the Alternate Display Switching circuit (Diagram 6) is LO,
and Q283 is biased off. This puts A/B SWP SEP poten
tiometer R280 in the circuit where it can affect the bias
level on one side of the differential current source formed
by Q284 and Q285. Changing the bias adds a dc offset
current to the Vertical Output Amplifier that moves the B
trace vertically with respect to the A trace.
During the Nonstore A sweep interval, the SEP signal is
HI, and Q283 is turned on to isolate potentiometer R280
from the biasing circuit of Q284. The base voltages of
Q284 and Q285 are then equal. With the same bias to
both sides of the Vertical Output Amplifier, no offset is
added to the A trace. In STORE mode, the HI STORE sig
nal placed on the base of Q282 keeps Q283 off, and the
A/B Sweep Sep circuit on.
TRIGGERING
The Trigger Amplifiers, shown on Diagram 4, provide
trigger signals to the Sweep Generators from either the
Vertical Preamplifiers, the EXT INPUT connector, or the
power line. The A&B INT switch selects either Channel 1
or Channel 2 as the trigger source, and the A SOURCE
switch selects between internal, line, or external trigger
sources. See Figure 3-4 for the block diagram of the
trigger amplifiers and switching circuitry.
Internal Trigger Pickoff
Signals from the Vertical Preamplifiers drive the CHI
and CH2 Internal Trigger Amplifiers with channel selection
determined by the VERTICAL and HORIZONTAL MODE
switches. Trigger signal pickoff from Channel 1 is done by
Q302 and 0303, and Q327 and Q328 pick off the Chan
nel 2 internal trigger signal. The circuitry associated with
Channel 2 is the same as that for Channel 1 except for a
trigger offset adjustment. Channel 1 trigger signal circuitry
is described; equivalent components in Channel 2 perform
identically.
Differential
vertical
signals
from
the
Channel 1
Preamplifier go to Q302 and Q303. These emitter-follower
transistors each drive one input transistor in trigger
preamplifier 1C U310. The collectors of the U310 input
transistors in turn supply emitter current to a pair of two
current-steering transistors. A compensation and biasing
network is connected between the emitters of the input
transistors. Trigger Offset potentiometer R309 in the
emitter circuit adjusts the bias levels of the two input
transistors of U310 to match the dc offsets of the Chan
nel 1 and Channel 2 Trigger Amplifiers.
3-13
Содержание 2230
Страница 12: ...2230 Service X The 2230 Digital Storage Oscilloscope 4998 01 ...
Страница 32: ...Operating Information 2230 Service 4998 04 Figure 2 4 Power and display controls and power on indicator 2 5 ...
Страница 33: ...Operating Information 2230 Service Figure 2 5 Vertical controls and connectors 2 6 ...
Страница 48: ...Operating Information 2230 Service Figure 2 11 X Y Plotter interfacing ...
Страница 56: ...Theory of Operation 2230 Service 4999 01 3 2 Figure 3 1 Simplified block diagram ...
Страница 68: ...Operating Information 2230 Service Figure 2 11 X Y Plotter interfacing ...
Страница 76: ...Theory of Operation 2230 Service 4999 01 3 2 Figure 3 1 Simplified block diagram ...
Страница 82: ...Theory of Operation 2230 Service 510 499 9 02 Figure 3 2 Block diagram of the Channel 1 Attenuator circuit 3 8 ...
Страница 98: ...Theory of Operation 2230 Service 499 9 06 Figure 3 6 Horizontal Amplifier block diagram 3 24 ...
Страница 111: ...Theory of Operation 2230 Service 3 37 Figure 3 9 Acquisition Memory timing ...
Страница 190: ...Maintenance 2230 Service 999 14 Figure 6 3 Isolated kernel timing 6 9 ...
Страница 218: ...Maintenance 2230 Service 4999 37 Figure 6 7 Location of screws and spacers on the Storage circuit board 6 37 ...
Страница 329: ...PUT Figure 9 2 S em ico n d u cto r lea d co n fig u ratio n s ...
Страница 332: ...2230Service CHASSIS MOUNTED PARTS ...
Страница 334: ...A14 CH 1 LOGIC BOARD ...
Страница 337: ......
Страница 344: ...u sr z z o 1 ...
Страница 347: ...i n 5 a O Q q o u S a o h UJ s a b c d e f g h j k l m n ...
Страница 352: ......
Страница 355: ...WAVEFORMS FOR DIAGRAM 5 4999 83 ...
Страница 358: ...I W L U O U rc a 4 2 s ...
Страница 361: ...WAVEFORMS FOR DIAGRAM 6 S 84 ...
Страница 362: ...2230 Service TEST SCOPE TRIGGERED ON U665 PIN 8 FOR WAVEFORMS 31 THROUGH 33 ...
Страница 365: ... I I ...
Страница 366: ...A 1 6 S W E E P R EFEREN CE BOARD FIG 9 17 2230 Service Figure 9 17 A16 Sweep Reference board ...
Страница 369: ... o 0 UJU sa eg aiu c u J in su eg 5 C sis n g e s o N QO ...
Страница 371: ...Static Sensitive Devices See Maintenance Section CM I rv CD o 2230 Service ...
Страница 378: ......
Страница 384: ... I I c o C u o a 5 r O tD v j If 3 IV if I I ci if 5 3 I ...
Страница 386: ......
Страница 388: ...H K L M N 7 8 8 2 2 3 0 INPUT OUTFUT WIRING INTERCONNECT ...
Страница 392: ...W A V E F O R M S F O R D IA G R A M 14 ...
Страница 393: ...2230Service 0 0 d s t 4 9 9 9 9 5 ...
Страница 394: ...2230 Service TEST SCOPE TRIGGERED ON U911 PIN 21 FOR WAVEFORMS 64 THROUGH 69 4999 92 ...
Страница 396: ... ...
Страница 397: ...WAVEFORMS FOR DIAGRAM 15 TEST SCOPE TRIGGERED ON U9111 PIN 21 FOR WAVEFORMS 70 THROUGH 77 ...
Страница 399: ......
Страница 403: ......
Страница 404: ......
Страница 405: ......
Страница 406: ...2230 Service n CD O O i 0 s a f s s o m O F ig u re 9 5 D e ta ile d S to ra g e b lo c k diagram 4999 22 ...
Страница 409: ......
Страница 415: ...IMF PU TPR A IR TM FQ U I W A V E F O R M SF O RO IA G R A M1 5 W A V E F O R M SF O R i ...
Страница 417: ...4999 9S ...
Страница 419: ...i s 5 0 C C p F 2 CC p 2 a u 4 I s c c O 2 e e o 5 a o 5 i 2 i f 2 E C 52 ...
Страница 421: ...TEST SCOPE TRIGGERED ON U4105 PIN 9 FOR WAVEFORMS 121 AND 122 TEST SCOPE TRIGGERED ON U4227 PIN 10 i 4999 97 ...
Страница 423: ...W A V E F O R M SF O RD IA G R A M1 8 O c n ...
Страница 424: ...Figure 9 22 A11A1 Input Output board ...
Страница 427: ...WAVEFORMS FOR DIAGRAM 19 TEST SCOPE TRIGGERED ON U6103 PIN 1 FOR WAVEFORMS 126 AND 127 4999 98 ...
Страница 430: ...Figure 9 23 A11A2 Vector Generator board ...
Страница 434: ...49 9 9 tOO ...
Страница 436: ......
Страница 437: ...22 3 0 S ervice W A V E F O R M S F O R D I A G R A M 2 1 m f n h ...
Страница 442: ...WAVEFORMS FOR DIAGRAM 22 4999 78 ...
Страница 443: ...XY PLOTTER BOARD DIAGRAM 22 See Parts List for serial number ranges ...
Страница 444: ... u i o IO U J J i o D U I 1 t ir u j t O 0 X I c a a 3 4 2230 4999 71 REV FE8 1987 XY PLOTTER BOARD 22 ...
Страница 447: ...A21 RS 232 OPTION BOARD Flfi A 9 K 01 01 W M ...
Страница 450: ......
Страница 452: ...COMPONENT NUMBER EXAMPLE ...
Страница 455: ...r n n i i i i n O T IA ll D A A o n XY PLOTTER BOARD P in A23 OPTION MEMORY BOARD FIG 9 27 A22 GPIB OPTION BOARD ...
Страница 459: ...A16 SWEEP REFERENCE ADJUSTMENT LOCATION ...
Страница 467: ...2230 Service ...
Страница 468: ......
Страница 474: ......
Страница 475: ...2230 Service ...
Страница 476: ...2230 Service ...
Страница 477: ... D ...
Страница 483: ...2230 Service ...