HP 211B Service manual

Re]
OPERATING AND SERVICE MANUAL
MODEL 211B
SQUARE WAVE GENERATOR
SERIALS PREFIXED: G 621
COPYRIGHT HEWLETT-PACKARD GMBH !I966
BOBLINGEN, WESTERN GERMANY
PRINTED: JUNE , 66
o02iI - 90000

Table of Contents
TABLE OF CONTENTS
Section ; Page
I GENERAL INFORMATION. ......... 1-1
1-1. Description. ............. 1-1
1-4. Manual Identification. ........ 1-1
II INSTALLATION. .............. 2-1
2-1. InitialInspection........... 2-1
2-4. Claims and Repacking........ 2-1
2-7. Preparation for Use......... 2-1
2-10. Installation. ............. 2-1
2-12. Rack Mounting. ........... 2-1
II OPERATION. .........-2+082806458 3-1
3-1. Introduction. ............ 3-1
3-3. Duty Cycle. ............. 3-1
3-6. Operating Procedures........ 3-1
3-8. Free Running Mode........ 3-1
3-10. Sync Signals. ........... 3-1
3-12. Trigger Output.......... 3-1
IV. PRINCIPLES OF OPERATION. ....... 4-1
4-1, Introduction. ............. 4-1
4-3. General Description. ........ 4-1
4-9, Schematic Theory......... 4-2
4-10. Frequency Control Network. . . . 4-2
4-12. Current Source. .......... 4-2
4-13. Switching Circuit.......... 4-2
4-14. Ramp Capacitor Amplifier. .... 4-2
4-15, Schmitt Trigger. ......... 4-3
ii
Model 211B
Section Page
4-16. Syne Input Cirevit.........2.. 4-3
4-17. Trigger Output Circuit........ 4-4
4-18. 6002 Amplifier. ........... 4.4
4-19. 502 Amplifier... .......... 4-4
4-20. Power Supply. ............ 4-4
MAINTENANCE. ............0.. 5-1
5-1. Introduction. ............. 5-1
5-3. Test Equipment............ 5-1
5-5. Instrument Cover Removal. ..... 5-1
0-7. Performance Check.......... 5-1
5-9. Repetition Rate. .......... 5-1
5-10. Symmetry Control Check. .... 5-3
5-11. Output Pulse Characteristics. . . 5-3
5-13. 902 Output... .. Hes atl oe Shs hs 0-4
5-16. 6002 Output... ......04, 5-4
5-19. Synchronization... ........ 5-5
5-21. Trigger Output. .......... 5-5
5-23. Power Supply. ........... 5-6
5-25. Troubleshooting. ........... 5-6
5-28. Repair and Replacement. ...... 5-6
5-30. Component Identification. .... 5-6
5-34. Servicing Etched Circuit
Boards: . 06 ses ee See ee 5-6
REPLACEABLE. ............ . 6-1
6-1. Introduction.............. 6-1
6-3. Ordering Information......... 6-1

List of Illustrations and Tables
LIST OF ILLUSTRATIONS
Model 211B
Number Title Page
"1-1. Model 211B Square Wave Generator, ... 1-1
2-1. The Combining Case............ 2-0
2-2. Steps to Place Instrument in Combining
CASE? ie ave fark Geko ar els sel dS 2-0
2-3, Adapter Frame Instrument Combinations. .2-1
2-4. Two Half Modules in Rack Adapter. .... 2-2
3-1. Definition of Output Pulse Characteristics. 3-1
3-2, Front Panel Description. ......... 3-2
4-1. Basic Block Diagram. ........... 4-1
4-2. Simplified Current Source Operation. . . . 4-2
4-3. Ramp Capacitor Amplifier Block Diagram. 4-3
4-4. Synchronizing Operation.......... 4-3
Number Title Page
5-1. Definition of Output Pulse Characteristics. 5-1
5-2. Dial Accuracy Check. ........... 5-3
5-3. 502 Output Pulse Check. .......... 5-4
5-4, 6002 Output Pulse Check.......... 5-4
5-5. External Pulse Synchronization. ..... 5-5
5-6. Trigger Output Pulse Check........ 5-5
5-7. Component. Location on A2 Board. ..., 5-8
5-8. Repetition Rate, Synchronizing and Trigger
Output Circuit Schematic Diagram. 5-9/5-10
5-9. Power Supply Circuit Schematic Diagram. 5-11
5-10. Component Location, top view...... 5-12
5-11. Output and Attenuator Circuits Schematic
Diagrams i350 es bs wow eee ke. So we 5-13
LIST OF TABLES
Number Title Page
1-1. Model 211B Specifications. ........ 1-0
5-1. Required Test Equipment.......... 5-2
5-2. Dial Accuracy. ........6.2.50+02e005 5-3
Number Title Page
5-3. Schematic Diagram Notes.......... 5-7
6-1. Reference Designation Index........ 6-2
6-2. Replaceable Parts............ . .6-8
Hii

Specifications
Model 211B
Specifications
50 and 600 ohm Outputs
SYMMETRY CONTROL: Continuously variable from
25% - 75% duty cycle.
POLARITY: Negative 6
PHASE DIFFERENCE: 180° between 502 and 600Q
outputs at 50% duty cycle.
50 ohm Output
SOURCE IMPEDANCE:
approximately 15pF.
PULSE SHAPE: (Measured at 5 V across 502)
RISE AND FALL TIMES: < 5ns .
OVERSHOOT AND RINGING: < 5% peak of pulse
amplitude.
PRESHOOT: <5%
502 +*3% shunted by
AMPLITUDE
MAXIMUM OUTPUT: 5V across 502, 10V
across an open circuit. Output circuit protec-
ted, cannot be damaged by shorting.
ATTENUATOR: Provides 7 steps from 0.05 to
5 Vinal, 2.5, 5 sequence.
VERNIER: Provides continuous adjustment be-
tweenranges, minimum output less than 0.02V
across 502. Rotating vernier to minimum
(ccw) may increase preshoot to 10%.
600 ohm Output
SOURCE IMPEDANCE: 6002 410%
PULSE SHAPE
RISE AND FALL TIMES: < 70ns across
6002, less than140ns across anopencircuit.
Decreased amplitude setting will improve
rise time.
OVERSHOOT AND RINGING: < 5%
AMPLITUDE
MAXIMUM OUTPUT: 30 V across 6002, 60 V
across an open circuit.
ATTENUATOR: Providescontinuous adjustment
from full output to less than 0.3 V across
6002.
1-0
Repetition Rate and Trigger Output
FREE RUN
REPETITION RATE
502 output: 1 Hz to 10 MHz, 7 ranges
6002 output: 1 Hzto 1MHz, 6 ranges
DIAL CALIBRATION: 1 - 10 (linear)
DIAL ACCURYCY: +5% to 10 MHz at 50% duty
cycle. Variation of symmetry control may
change frequency and additional +5% (10% on
10 MHz range).
PERIOD JITTER: < 0.2% at any duty cycle and
repetition rate setting.
SYNCHRONIZATION
SYNC INPUT: DC coupled, sine waves or positive
pulses from 1 Hz to 10 MHz. Frequency of
synchronizing signal must be 105% - 140%
of dial setting.
SENSITIVITY: Willsynchronizeon positive pulses
of at least 1 V, sine waves of at least 2V
peak to peak.
INPUT IMPEDANCE: Approximately 5002
TRIGGER OUTPUT PULSE: (suitable for synchroni-
zation with another 211B).
WIDTH: 10 (+5) ns at 50% points.
AMPLITUDE: At least 2 V across 502
TIMING: Coincident with leading edge of 502 pulse
POLARITY: Positive or Negative
General
POWER: 115 or 230 V 10% - 15%, 50 Hzto 400 Hz,
23 W.
DIMENSIONS:
WEIGHT: Net, 9ibs (4kg). Shipping 11 lbs (5kg)

Model 211B
Section I
Paragraphs 1-1 to 1-5
SECTION |
GENERAL INFORMATION
1-1. DESCRIPTION.
1-2. The -hp- Model 211B Square Wave Generator
(shown in Figure 1-1) is a compact, general purpose
instrument providing negative pulses of variable fre-
quency, symmetry and amplitude. Complete specifi-
cations of performance are given in Table 1-1. Two
independent outputs are available. The 502 source
supplies pulses with 5ns rise and fall times and a
peak output of 5 volts across 502. Simultaneously,
a 6002 source provides pulses of 30 volts across
6002 having a rise and fall time of 70ns. Matched
output impedance provide twice the voltage across
an open circuit. Amplitude for both pulses is
seperately controllable. The frequency range of the
instrument, 1 Hz to 10 MHz, is covered in 7 decade
ranges with a linearly calibrated dial for continuous
adjustment on all positions. The 502 output oper -
ates to 10 MHz, the 6002 output to 1 MHz. The
duty cycle can be varied from 25% to 75%.
1-3. Trigger output pulses, for synchronizing exter -
nal circuits or instruments, have a pulse width of less
than 20ns, reversible polarity and an amplitude of at
ro. Fal 218 SQUARE WAVE
HEWLETT PACKER
least 2 volt across 502. The trigger output is coin-
cident with the leading edge of the 502 output. The
211B operates free running or may be synchronized
with external signals of either sinewaves or positive
pulses,
1-4. MANUAL IDENTIFICATION.
1-5. Information in this manual applies directly to
Modell 211B instruments with serial prefix of G- 621
The serial prefix is the first three digits of the eight-
digit serial number (e. g. 000-00000) used to indentify
each -hp- instrument. If the serial prefix of a Model
211B is not G-621, a manual change sheet supplied
with the manual will define the differences between
that Model 211B and the one described in this manual,
or a different manual will provide correct informa-
tion. Corrections to this manual, due to errors that
existed when it was printed, are called Errata and
appear only on the change sheet supplied. To obtain
correct manual information for any instrument, con-
tact the nearest Hewlett-Packard Company Sales/Serv-
ice Office and always specify the model number and
serial number.
Figure 1-1 Model 211B Square Wave Generator
1-1

Model 211B
Section II
Figure 2-1 and 2-2
DIVIDER ASSEMBLY
DIVIDER LATCH RETAINER
Figure 2-1 The Combining Case
oO
INSERT DIVIDER, ENGAGING
TABS IN TOP AND BOTTOM
MOUNTING SLOTS
@
PUSH
RETAINER
DOWN
TWIST DIVIDER TO VERTICAL TORELEASE
POSITION
©
SLIDE INSTRUMENT
©) : mee INTO CASE
PUSH IN TO LIMIT
@
TO SET RETAINER BACK IN
PLACE, ENGAGE HOOKS FIRST
4) ON ONE SIDE OF DIVIDER,
THEN ON OTHER
SLIDE LATCH TO LOCK
DIVIDER
PUSH RETAINER UP TO LOCK
Figure 2-2 Steps to Place Instrument in Combining Case

Model 211B
Section IT
Paragraphs 2-1 to 2-13
SECTION Il
INSTALLATION
2-1. INITIAL INSPECTION.
2-2. MECHANICAL INSPECTION. If external
damage to the shipping carton is evident, ask the
carrier’s agent to be present when the instrument is
unpacked. Check the instrument for external dam-
age such as broken controls or connectors, and dents
or scratches on the panel surfaces. If damage is
evident, see Paragraph 2-4 for recommended claim
procedure and repackaging information. If the ship-
ping carton is notdamaged, check the cushioning mat-
erial and note any signs of severe stress as an in-
dication of rough handling in transit. If the instru-
ment appears undamaged, perform the electrical
check given in the following paragraph.
2-3. ELECTRICAL CHECK. Check the electrical
performance of the Model 211B as soon as possible
after receipt. Paragraph 5-7 through 5-22contain
performance check procedured which will verify in-
strument operation within the specification listed in
Table 1-1. This check is also suitable for incoming
quality control inspection. If the Model 211B does
not perform within the specifications when received,
refer to Paragraph 2-4 for recommended claim pro-
cedure and repacking information.
2-4. CLAIMS AND REPACKING.
2-5. Ifphysical damage is evident or if the instru-
ment does not meet specifications when received, no-
tify the carrier and the nearest Hewlett-Packard
Sales/Service Office (see list at rear of this manual).
Refer to inside front cover of this manual for the
Warranty statement applicable of all Hewlett-Packard
instruments and products. The Sales/Service Office
will arrange for repair or replacement of the instru-
ment without waiting for settlement of the claim
against the carrier.
2-6. The original shipping carton and packing mate-
rial, with theexception of the accordian-pleated pads,
should beused for reshipment. The accordian-pleated
pads are fatiqued with one use and are not reusable.
The Hewlett-Packard Sales/Service Office will
also provide information and recommendations on
materials to be used if the original packing material
is not available or is not reusable. Materials used
should include: (1) a double walled carton (check
with a freight carrier for test strength required),
(2) heavy paper or sheets of cardboard to protect all
instrument surfaces; use extra material around
projecting parts of the instrument, (3) at least four
inches of tightly-packed shock-absorbing material
surrounding the instrument. Close the carton securely
with heavy paper tape. If the instrument is to be
shipped to a Hewlett-Packard Sales/Service Office
for repair, attach a tag showing owner, model,
serial number and repairs required.
2-7. PREPARATION FOR USE.
2-8. POWER SOURCE REQUIREMENTS. The
Model 211B may be operated from an ac source of
115 or 230 volts (+10%, -15%) at|50 to 400 Hz!Pow-
fer dissipation is approximately 25 watts. With the
instrument power cord disconnected, move the slide
switch (located on rear panel) until the desired volt-
age numbers (115 or 230) arevisible. A narrow blade
screwdriver is recommended to position the slide
switch. The instrument power line fuse (located at
the rear of the instrument above the|power cord re-
ceptalcle) is a 0.5 ampere, slow-blow type for 115 v.
operation and a 0.25 ampere, slow-blow type for
230 v. operation.
2-9. THREE CONDUCTOR POWER CABLE. To
protect operating personnel, the National Electrical
Manufacturers’ Association (NEMA) recommends
that the instrument and cabinet be grounded. The
centre pin on the power cable is the ground connec-
tion. To retain the protection when operating the
instrument from a two-contact outlet, use a three-
conductor to two-conductor adapter and connect the
adapter wire to a suitable ground.
2-10. INSTALLATION.
2-11. The Model 211B is fully transistorized; there-
fore no special cooling is required. However the in-
strument should not be operated where the ambient
temperature exceeds 55° C,
2-12. RACK MOUNTING.
2-13. The Model 211B is a submodular unit that
when used alone can be bench mounted only. However
when used incombination with other submodular units
it can be bench and/or rack mounted. The -hp- com-
bining case and adapter frame are designed specif-
ically for this purpose.
FILLER PANEL
Figure 2-3 Adapter Frame Instrument Combinations
2-1

Section IT
Paragraphs 2-14 and 2-15
2~2
oO)
ADAPTER
SPACER CLAMP
RETAINING SCREWS
Figure 2-4 Two Half Modules in Rack Adapter
Model 211B
2-14. COMBINING CASE. The combining case is
a full-module unit which accepts varying combina-
tions of submodular units. Being a full-module unit,
it can be bench or rack mounted analogous to any full
module instrument, An illustration of the combining
case is shown in Figure 2-1 . Instructions for in-
stalling the Model 211B in a combining case are given
graphically in Figure 2-2.
2-15, ADAPTER FRAME. The adapter frame isa
rack frame that accepts any combination of sub-mod-
ular units. It can be rack mounted only. An illustration
of the adapter frame is given in Figure 2-3. To as-
semble, refer to Figure 2-4 and proceed as follows
a. Place the adapter frame (1) on edge of bench
as illustrated.
b. Stack the submodular units (2) in the frame.
Place the spacer clamps (3) between instru-
ments. ;
d. Place the spacer clamps (4) on the two end
instruments.
e. Push the combination into the frame.
Insert screws (5) on both sides of frame, and
tighten until submodular instruments are se-
cure in frame.
g. The complete assemble is ready for rack
mounting.

Model 211B
Section III
Paragraphs 3-1 to 3-13
SECTION Ill
OPERATION
3-1. INTRODUCTION.
3-2. This section contains the operating instructions
for the Model 211B Square Wave Generator. This in-
strument has been designed for general purpose lab-
oratory requirements withthe ease-of-use as a prime
consideration. Therefore the operating procedure is
quite simple. Figure 3-2 identifies and briefly
describes
the
pupose
of
each
panel
control
and
connector on the instrument.
3-3. DUTY CYCLE.
3-4. Duty cycle is defined as the ratio of duration of
pulse (i.e. pulse width) to the total duration of one
complete cycle. Figure 3-1 shows the relationship
which determines the duty cycle. The time for one
cycle is defined as the period, and the period is re-
lated to repetition rate by: ae 1
Period = Re5- Rate
Thus
the
product
of
pulse
width
and
frequency
mul-
tiplied
by
100
determines
the
duty
cycle
percentage.
3-5. The SYMMETRY control is responsible for the
duty cycle setting; the variability being 25 - 75 % of
the
period.
The
duty
cycle
remains
unchanged
when
external synchronizing signals are applied to the
Model 211B.
PULSE
[~ WIDTH |
AMPLITUDE
| PERIOD =
!
FREQUENCY
4 . -PULSE_WIDTH
%*DUTY CYCLE Sena ot
PULSE WIDTH x FREQUENCY x 100
Figure 3-1 Definition of Output Pulse Characteristics
3-6. OPERATING PROCEDURES.
3-7. The Model 211B canbe operated in two different
modes, free-running or synchronized with external
signals. The procedures are detailed in Paragraphs
3-8 through 3-13.
3-8. FREE-RUNNING MODE
3-9. The Model 211B will generate internally any
repetition rate from 1 Hz to 10 MHz (1 MHz at 600 2
output). The repetition rate is established by setting
the MULTIPLIER selector to any of the seven inter-
nal ranges and then adjusting the FREQUENCY (Hz)
control to the specific rate desired.
To operate proceed as follows :
(a) Push instrument LINE switch on.
(b) Set MULTIPLIER to desired range and adjust
FREQUENCY (Hz) to exact position for frequency
desired.
(c) Adjust SYMMETRY for desired duty cycle.
(d) 502 OUTPUT. Select AMPLITUDE range and
VERNIER setting desired. Note that the cw
position of the VERNIER yields at least that
indicated voltage on the AMPLITUDE selector
switch.
(e) 6002 OUTPUT. Adjust AMPLITUDE setting as
desired. Note that the specified amplitude is
across a 6002 load. Twice the voltage will be
obtained across an open circuit.
3-10 SYNC SIGNALS
3-11. The Model 211B may be synchronized by ex-
ternal signals of either 1 volt positive pulses or 2 V
peak to peak sinewaves applied to the SYNC INPUT
connector. External signals with frequencies of 105%
to 140% of the internal setting of the 211B can be
synchronized. If the 211B is not in synchronism with
an external signal compare dial and range settings
with the frequency of the external signal.
3-12. TRIGGER OUTPUT.
3-13. Trigger pulses are available at the front panel
of the Model 211B. A positive or negative pulse,
selected by TRIGGER POLARITY switch and coin-
cident with the leading edge of the 502 output pulse,
is available at the trigger output connector.
3-1

Section II
Figure 3-2
®
3-2
211B SQUARE WAVE GENERATOR
HEWLETT PACKARD
Ke) |
FREQUENCY (Hz)
100
LINE
PUSH ON/OFF
SYNC.INPUT
(i2) W)
LINE switch. Controls AC power to instrument
and indicates "on" position by glowing red.
FREQUENCY dial. Provides continuous cal-
ibrated control of the output frequency within the
range determined by the MULTIPLIER setting.
FREQUENCY MULTIPLIER switch. Selects the
operating range of the FREQUENCY dial.
SYMMETRY control. Provides adjustment of duty
cycle of output pulses.
AMPLITUDE selector switch. Selects amplitude
range of the 502 output pulse.
AMPLITUDE VERNIER control. Provides contin-
uous adjustment of the 502 output pulse between
settings of the AMPLITUDE selector switch.
Maximum CW position gives at least the voltage
shown on the AMPLITUDE selector switch.
Figure 3-2
SYMMETRY
MULTIPLIER
IK
0 _j-
TRIGGER
OUTPUT
Model 211B
AMPLITUDE
(VACROSS 50.0;
AMPLITUDE VERNIER
OUTPUT OUTPUT
600n 5302
6
0) @) @
OUTPUT -50 connector.
pulse.
Supplies 502 output
AMPLITUDE control. Provides uncalibrated
control of 600Q output amplitude.
C* [TPUT-6002 connector. Supplies 6002 output
pulse.
TRIGGER POLARITY switch. Selects either pos-
itive or negative TRIGGER OUTPUT pulse.
TRIGGER OUTPUT connector. Supplies trigger
output pulse.
SYNC INPUT connector. Input connector for
external synchronizing signals.
Front Panel Description