Tektronix 2445, 2465 User Manual

'DBktroniK

®

COMMITTED

TO

EXCELLENCE

Tektronix, Inc.
P.O. Box 500
Beaverton,

Oregon 97077 Serial Number

PLEASE CHECK FOR CHANGE INFORMATION
AT THE REAR OF THIS MANUAL.

2445/2465

OPTION 05

TV OPTION

OPERATORS

INSTRUCTION MANUAL

070-4629-00 First Printing OCT 1983
Product Group 38 Revised MAY 1984

Copyright '^' 1983 Tektronix, Inc. All rights reserved.
Contents of this publication may not be reproduced in any
form without the written permission of Tektronix, Inc.

Products of Tektronix, Inc. and its subsidiaries are covered
by U.S, and foreign patents and/or pending patents.

TEKTRONIX, TEK, SCOPE-MOBILE, and ^^ a""®

registered trademarks of Tektronix, Inc. TELEQUIPMENT

is a registered trademark of Tektronix U.K. Limited.

Printed in

are reserved.

Each instrument has a serial numtjer on a panel insert, tag,
or stamped on the chassis. The first numt)er or letter
designates the country of manufacture. The last five digits
of the serial number are assigned sequentially and are
unique to each instrument. Those manufactured in the

United States have six unique digits. The country of
manufacture is identified as follows:

BOOOOOO Tektronix, Inc., Beaverton, Oregon, USA
100000 Tektronix Guernsey, Ltd., Channel Islands
200000 Tektronix United Kingdom, Ltd., London
300000 Sony/Tektronix, Japan
700000 Tektronix Holland, NV, Heerenveen,

U.S.A.

Specification and price change privileges

INSTRUMENT SERIAL NUMBERS

The Netheriands

2445/2465 Option 05 Operators

TABLE OF CONTENTS

Page

LIST OF ILLUSTRATIONS ii
LIST OF TABLES ii
OPERATORS SAFETY SUMMARY iii

Section 1 SPECIFICATION

INTRODUCTION 1-1
STANDARD ACCESSORIES 1-1
PERFORMANCE CONDITIONS 1-1

Section 2 CONTROLS AND INDICATORS

FRONT-PANEL CONTROLS 2-1
READOUT DISPLAYS 2-3

Section 3 PREPARATION FOR USE

POWER-UP SEQUENCE 3-1

Kernel Test 3-1

Successful Power-Up Sequencing . . 3-1
POWER-DOWN SEQUENCE 3-1
TV PROTOCOL AND LINE-NUMBERING
FORMAT SELECTION 3-1

Section 4 OPERATING CONSIDERATIONS

FRONT-PANEL CONTROL AND
SETUP CONSIDERATIONS 4-1

TV Clamp 4-1
A-FLD LINE # Control 4-1

Slope Selection 4-1
Display Considerations 4-1

Oscilloscope Dc Balance Routine ... 4-2

Front Panel Update 4-2

CH 2 SIGNAL OUT Connector 4-2
IDENTIFYING FIELDS, FRAMES, AND
LINES IN 525/60 AND 625/50 TV
SYSTEMS 4-2

NTSC (CCIR System M) 4-2

CCIR System B and Similar 625/50

Systems (including PAL) 4-2
GPIB CONTROLLABLE FUNCTIONS . . 4-3

Section 5 BASIC APPLICATIONS

Initial Setup 5-1

Signal Input Coupling 5-1

Time Interval Measurements 5-2

Voltage and IRE Measurements .... 5-2

CHANGE INFORMATION

Page

2445/2465 Option 05 Operators

Figure Page

The 2445 Option 05 (TV) Oscilloscope iv

The 2465 Option 05 (TV) Oscilloscope iv
2-1 TV Option front-panel controls 2-2
5-1 Appearance of video signal with CH 2 Input Coupling switch positions 5-1

LIST OF ILLUSTRATIONS

LIST OF TABLES

Table Page

1-1 Option 05 Electrical Characteristics 1-2

1 -2

Option 05 Mechanical Characteristics 1-3

4-1 GPIB Command Set for the TV Option 4-4

OPERATORS SAFETY SUMMARY

The

general safety summary in this part of the summary is for both operating and servicing

cautions will be found throughout the manual where they apply and do not appear

2445/2465 Option 05 Operators

personnel.

in

this summary.

Specific warnings and

Terms in This Manual
CAUTION Statements identify conditions or practices that

could result in damage to the equipment or other property.
WARNING statements identify conditions or practices that

could result in personal injury or loss of life.

Terms as Marked on Equipment
CAUTION indicates a personal injury hazard not immedi-

ately accessible as one reads the markings, or a hazard to
property, including the equipment

DANGER indicates a personal injury hazard immediately ac-

cessible as one reads the marking.

Symbols as Marked on Equipment

This symtx)! indicates where applicable
cautionary or other information is to be found.

Protective ground (earth) terminal.

itself.

Grounding the Product
This product is grounded through the grounding conductor

of the power
cord into a properly wired receptacle t)efore connecting to
the product input or output terminals. A protective ground
connection by way of the grounding conductor in the power
cord is essential for safe operation.

Danger Arising From Loss of Ground
Upon loss of the protective-ground connection, all accessi-

ble conductive parts (including knobs and controls that may
appear to be insulating) can render an electric shock.

Use the Proper Power Cord
Use only the power cord and connector specified for your

product.
Use only a power cord that is in good condition.

Use the Proper Fuse

To avoid fire hazard, use only a fuse of the correct type,

voltage rating and current rating as specified in the parts list

for your product.

cord.

To avoid electrical shock, plug the power

A

Power Source

This product is intended to operate from a power source
that does not apply more than 250 volts rms between the

supply conductors or between either supply conductor and
ground,
grounding conductor in the power cord is essential for safe
operation.

ATTENTION — Refer to manual.

A protective ground connection by way of the

Do Not Operate in Explosive Atmospheres

To avoid explosion, do not operate this product in an explo­sive atmosphere unless it has t}een specifically certified for
such operation.

Do Not Remove Covers or Panels
To avoid personal injury, do not remove the product covers

or panels. Do not operate product without the covers and
panels properiy installed.

Ill

2445/2465 Option 05 Operators

The 2445 Option 05 (TV) Oscilloscope.

IV

The 2465 Option 05 (TV) Oscilloscope.

SPECIFICATION

Section 1

2445/2465 Option 05 Operators

INTRODUCTION

The TEKTRONIX 2445 and 2465 Oscilloscopes with Op­tion 05 (TV Option) have additional hardware and software
features to simplify triggering and viewing of television
nals.

The option adds TV (back-porch) clamp circuitry to the
Channel 2 input and TV trigger coupling modes are pro­vided,

allowing a user to select either horizontal or vertical
sync pulses to obtain horizontal-line-sync or field-sync pulse
triggering.
cific line number within a TV field and provides sync polarity
switching for either sync-negative or sync-positive compos­ite video signals.

able,
numbering protocols. Stable video rejection and sync
separation is obtained from sync-positive or sync-negative,
interlaced or non-interlaced scan, composite video signals
having 525 to 1280 horizontal lines per frame and 50- or
60-Hz field rates.

This option permits the user to trigger on a spe-

NOTE

Composite video is the picture waveform complete

with vertical and horizontal blanking and sync. Com­posite sync is combined vertical and horizontal sync
as a single waveform, but without video (picture)

waveforms.

Both system-M and nonsystem-M protocols are avail-

providing compatibility with most television signal line-

sig-

STANDARD ACCESSORIES

In addition to the standard accessories listed in the basic
oscilloscope manuals, the following TV Option accessories
are provided:

Quantity

1

1

1
1
1

Description

2445/2465 Option 05,
TV Option, Operators Manual

2445/2465 Option 05,
TV Option, Service Manual

CCIR Graticule
NTSC Graticule
Polarized Viewing Hood

Part Number

070-4629-00

070-4630-00

378-0199-01
378-0199-02
016-0180-00

PERFORMANCE CONDITIONS

Except as noted in Tables
electrical,
TV Option instruments are identical to those specified for
basic instruments in the respective 2445 and 2465 Oscillo­scope manuals.

environmental, and mechanical characteristics of

1 -1

and

1 -2

of this

manual,

the

1-1

Specification
2445/2465 Option 05 Operators

Table 1-1

Option 05 Electrical Characteristics

Characteristics

Frequency Response

Full Bandwidth

50 kHz to 5 MHz
>5 MHz to 10 MHz
>10 MHz to 30 MHz

Bandwidth Limit

50 kHz to 5 MHz

Square Wave Flatness

Field Rate

Performance Requirements

VERTICAL DEFLECTION SYSTEM—CHANNEL 1 AND CHANNEL 2

For VOLTS/DIV switch settings between 5 mV and 0.2 V/div with VAR
control in calibrated detent. Five-division, 50 kHz reference signal from a
50 fi system. With external 50 fi termination on 1 Mfi input.

Within ±1%.
Within

4-1%,

-2%.

Within 4-2%, -3%.

Within

4-1%,

-4%.

With fast-rise step (rise time^l ns), 1 Mfi dc input coupling, an external
50 fi termination, and VAR VOLTS/DIV control in calibrated detent.
Exclude the first 50 ns following the step transition. For signals with rise
times =s10ns, add 2% p-p between 155 ns and 165 ns after step
transition.

5mV/divto lOmV/div

20 mV/div

50 mV/div

Line Rate

5mV/div to lOmV/div

20 mV/div

50 mV/div

TV (Back-Porch) Clamp (CH 2 only)

60 Hz Attenuation

Back-Porch Reference

1.5% p-p at 60 Hz with input signal of 0.1 V.

1%

p-p at 60 Hz with input signal of 0.1 V.

1%

p-p at 60 Hz with input signal of 1.0 V.

1.5% p-p at 15 kHz with input signal of 0.1 V.

1%

p-p at 15 kHz with input signal of 0.1 V.

1%

p-p at 15 kHz with input signal of 1.0 V.

For VOLTS/DIV switch settings between 5 mV and 0.2 V with VAR
control in calibrated detent. Six-division reference signal.

^18 dB.

Within 1.0 division of ground reference.

1-2

REV MAY 1984

2445/2465 Option 05 Operators

Table 1-1 (cont)

Characteristics Performance Requirements

TRIGGERING

Specification

Sync Separation

Trigger Modes

Main Sweep

Delayed Sweep

Input Signal Amplitude for Stable Triggering

Channel 1 or Channel 2

Composite Video
Composite Sync

Channel 3 or Channel 4

Stable video rejection and sync separation from sync-positive or sync­negative composite video, 525 to 1280 lines, 50 Hz or 60 Hz, interiaced
or noninterlaced systems.

All lines:

Field 1, selected line
Field 2, selected line (1 to n);
Alt fields, selected line (1 to n);

where n is equal to or less than the number of lines in the frame and less
than or equal to 1280.

Delayed by time.

Minimum for peak signal amplitude within 18 divisions of input ground
reference.

1 division.
0,3 division.

Minimum for peak signal amplitude within 9 divisions of input ground
reference.

(1

to n);

Composite Video
Composite Sync

Characteristics

Weight

With Power Cord,
Operators Manual, and Options

Domestic Shipping Weight

Cover,

0.5 division.

0.25 division.

Table 1-2

Option 05 Mechanical Characteristics

Description

Pouch, Probes,

«12.0 kg (26.4 1b).
«17.6kg(38.8 1b).

1-3

2445/2465 Option 05 Operators

CONTROLS AND INDICATORS

Section 2

FRONT-PANEL CONTROLS

Certain front-panel controls on the oscilloscope have
dual modes of operation when the TV Option is installed.
When the TV Option is enabled, the controls have the func­tions as described below. When the TV Option is not en­abled,

the controls have the functions described in the
oscilloscope Operators manual and in other option Oper­ators manuals if other options are installed.

See Figure 2-1 for the location of the TV Option front-

panel controls.

(in CH 2 Input Coupling Switch—Selects or deselects

the TV (back-porch) clamp function.

UPiTV CLAMP—Activates the TV (back-porch)
clamp when the switch is pushed up from the 1 Mfi
AC position. The AC indicator LED will remain on
and the message "TVC will appear on the top line
of the crt. The clamp sets the television signal
back-porch amplitude to a constant dc level and
eliminates vertical drift, hum, and tilt in the display,
A stable display is provided despite changes in
nal amplitude and average luminance levels. The
TV (back-porch) clamp can be enabled even if TV
trigger is deselected,

AC—Deactivates the TV (back-porch) clamp when
the switch is pushed down once from the UP:TV
CLAMP position. The AC indicator LED will remain
on and the message "TVC will be removed from
the top of the crt. The television signal's level will
then be set by the average signal level and vary
with that average level.

sig-

the "Operating Considerations" section of this
ual for further information about using this control.

When the line number setting reaches the maximum
number of lines in a field and either FLD 1 or FLD 2
coupling is selected, additional clockwise turning of
the control changes the line number to the t)eginning
of the following
pling (ALT) is selected, further rotation of the control
past the maximum number will only reset the count
to1.

When the line numt)er setting reaches 1 and either
FLD 1 or FLD 2 coupling is selected, counterclock­wise rotation of the control will move the line number
to the maximum line number of the previous
ALT coupling is selected, the line number will move
to the maximum line number common to txjth fields.

See the "Line Numtjer Format Selection" discussion
in the "Preparation for Use" section of this manual

to choose the desired line number format. See the
example t»elow for operation with a 525-line inter­laced scan signal.

Format 1 .. I 1 2
Format 2 . , I 1 2
Field I

FLD LINE #

Control Rotation

field.

If alternate FLD 1-FLD 2

, . 263 ll 2 ... 2621

.. 263 1264 . . . 5251

1 I 2 I

CCW-

-^CW

man-

cou-

field.

If

(32) A-FLD LINE # Control—Selects a specific line

number within the field for triggering the oscillo­scope when the TV Option is enabled and the
ger COUPLING switch is set to FLD 1, FLD 2, or
alternate FLD 1 -FLD 2 mode. Possible line numt)ers
range from 1 to the maximum number of lines per
frame in the television signal t>eing viewed. Rotating
the control clockwise increases the line numtier; ro­tating it counterclockwise decreases the line num­ber. See the "A-FLD LINE # Control" discussion in

Trig-

TRIGGER COUPLING Switch and

®

Indicators—Selects and indicates one of four
tional choices for trigger coupling. They are: FLD 1
(field 1), FLD 2 (field 2), ALT (altemate field
and LINES (horizontal TV-line sync triggering). The
crt readout will display the trigger coupling mode.

FLD

1—Sweep
input TV signal and the FLD 1 LED is illuminated,
NORM trigger mode is automatically selected.

is triggered on the first field of the

1-field

addi-

2),

2-1

Controls and Indicators
2445/2465 Option 05 Operators

3 VERTICAL

^POSITION

C

{) POSITION

•a "

CHI CH2-^ CH3 CH«

ADO J INVERT-

MODE ,

n n

a D

CHOP BW LIMIT

D D a D

aUT:ALT

20MN;

2-2

Figure

2-1.

TV Option front-panel controls.

4629-03

Controls and Indicators

2445/2465 Option 05 Operators

FLD 2—Sweep is triggered on the second field of
the input TV signal and the FLD 2 LED is illumi­nated.

NORM trigger mode is automatically

selected,
ALT—Sweep is alternately triggered by the two

TV fields and both the FLD 1 and FLD 2 LEDs are
illuminated.
selected.

When CHOP Vertical Mode is selected, all of the
active channels are triggered alternately by field
1 and field 2 of the video signal. The two fields
will appear overlayed.

When ALT Vertical Mode is selected and more
than one channel is displayed, field 1 of the
video signal will trigger the first active channel

and field 2 will trigger the next active channel.
When more than two channels are displayed,
each additional channel will be triggered first by
field 1 and then by field 2 of the video trigger
signal,

LINES—Sweep will trigger when the holdoff time
has elapsed and a TV horizontal line-sync pulse is

encountered. The LINES LED is illuminated and

AUTO trigger mode is automatically selected.

NORM trigger mode is automatically

and its two fields will be overiayed.

READOUT DISPLAYS

In addition to the readout displays for oscilloscope opera­tion shown in Sections 3 and 6 in the oscilloscope Oper­ators manual, an instrument equipped with the TV Option
will display option status information when in any of the TV
modes. Also see the "Operating Considerations" section of
this manual for additional information.

The crt readout will display TV Trigger information when
the Trigger COUPLING switch is set to any of the TV trigger
modes (FLD
(back-porch) clamp is active. The TV Option utilizes a dis­play area of up to
the right half of the top display line of the crt readout. If the
right half is not available, the TV Option information is dis­played in the left half of the top line.

When field triggering is selected, the readout displays the
line number selected for triggering the oscilloscope. The line
number readout is followed by a delta (A) symtxDl if the FLD
LINE # control is controlling the line number

A symbol is not present, the FLD LINE # control will not
change the line number selection. The crt readout displays
the message "TVC" whenever the TV (back-porch) clamp is
active.

1,

FLD 2, ALT, or LINES) or when the TV

12

characters that are normally located in

selection.

If the

2-3

2445/2465 Option 05 Operators

PREPARATION FOR USE

Section 3

This section of the manual contains information related
to the power-up of the main instrument containing the TV
Option.

The power-up sequence of the oscilloscope is de-

scribed,

error messages that may occur if the instrument is not func­tioning properly. Also included is initial setup information for
the selection of the TV protocol and line number format
parameters.

along with explanations of potential option-related

POWER-UP SEQUENCE

Before turning on power to the instrument, read Section

2,

"Preparation for Use," in the oscilloscope Operators
ual and follow the safety and precautionary information de­scribed there.

The power-up tests, automatically performed each time
the oscilloscope is turned
scope circuitry and the TV Option circuitry. Tests specifically
applicable to the TV Option are integrated into the power-up
tests for the host oscilloscope and include the TV Kernel
test.

Kernel Test

Operation of the TV Option memory (ROM) is checked by
the standard instrument Kernel test. Kernel test failures will
result in an attempt to flash the front-panel A SWP TRIG'D
indicator.

On some instruments having other options installed,

the A/B TRIG button may be labeled A/B/MENU.

on,

test both the standard oscillo-

NOTE

man-

Successful Power-Up Sequencing

When the power-up routine is successfully completed
without a failure indication, the oscilloscope enters the nor­mal operation state. The oscilloscope parameters are set to
correspond with current front-panel switch positions and
with switch functions that were established for at least 10
seconds before instrument power was last turned off. The
instrument is now ready to make measurements as
required.

POWER-DOWN SEQUENCE

When the POWER switch is set to OFF, the instrument
powers down and the instrument front panel settings that
were unchanged for at least 10 seconds prior to power off
will be stored for use the next time power is applied to the
instrument.

TV PROTOCOL AND LINE-NUMBERING

FORMAT SELECTION

The following procedures are used to select a particular
protocol or line-numb)ering format. Both involve access to
Diagnostic Monitor routines (EXER 61 and EXER 62) and
affect field triggering only (FLD
FLD 2). TV protocol selection allows the user to choose t>e­tween system-M and nonsystem-M protocols. Selecting the
incorrect system for a given TV protocol will not affect the
ability to trigger on a given TV waveform. It
cause the line number displayed to be inaccurate. Line­numtjering format selection allows the user to select a pre­ferred line-numb>ering scheme. Format 1 references line one
from the beginning of the field being used for trigger refer­ence.

Format 2 always references line one from the first line

of Field 1.

1,

Alternate FLD 1-FLD 2, or

will,

however,

Even with a Kernel failure, pressing in the A/B TRIG

switch may still place the instrument in an operating mode.

However, if the operating mode is successfully entered, in­strument operation may be unpredictable. If the instrument
then functions adequately for your particular measurement
requirement, it can be
technician for repair of the problem as soon as possible.

used;

but refer it to a qualified service

Exercise procedure TV EXER
loscope Diagnostic Monitor, allows the user to select be­tween system-M and nonsystem-M television protocols.
When system-M is selected, the line count begins three lines
before the field-sync pulse is encountered. If nonsystem-M
is selected, the line count tjegins coincident with the
sync pulse.

61,

accessed via the oscil-

field-

3-1

Preparation For Use
2445/2465 Option 05 Operators

Exercise procedure TV EXER 62, accessed via the oscil­loscope Diagnostic Monitor, allows the user to select one of
two line-number formats as shown below.

Format 1 .,I 1 2, ,. 263 ll 2 ... 2621
Format 2 .. I 1 2 ... 263 1264 ... 5251
Field I 1 I 2 I

FLD LINE #

Control Rotation

To choose or determine the TV protocol:

1.

Hold in both the AV and At buttons and push in the

TRIGGER SLOPE button to enter the Diagnositic Monitor.

2.

Repeatedly push up and release the TRIGGER MODE

switch until the message "TV EXER 61" appears at the

bottom-left corner of the crt.

3. Push up and release the COUPLING switch once, and
the currently selected protocol will appear at the top of the
crt. The message meanings are as follows:

LINE 1 OCCURS PRIOR TO FLD SYNC — System­M protocol is currently selected.

LINE 1 COINCIDENT WITH FLD SYNC — Nonsys­tem-M protocol is cun-ently selected.

CCW- —CW

4.

If the desired protocol message is not displayed, push

up and release the TRIGGER COUPLING switch once. The
desired protocol message should now be displayed. Push
down once on the TRIGGER COUPLING switch.

To choose or determine the line number format:

5. Push up and release the TRIGGER MODE switch.
The message "TV EXER 62" will be displayed at the bot­tom-left corner of the crt.

6. Push up and release the COUPLING switch once to
display the currently selected format at the top of the crt.
The message meanings are as follows:

LINE NO RESETS QN EACH FIELD—Fonnat 1 is
selected,

UNE NO RESETS QN FLD 1 ONLY-Format 2 is
selected.

7. If the desired line format message is displayed, exit
the Diagnostic Monitor by pushing the A/B TRIG button to
resume normal oscilloscope operation.

8. If the desired line format message is not displayed,
push up and release the TRIGGER COUPLING switch once.
The desired line format message should now be displayed.

9. Push the A/B TRIG button to exit the Diagnostic
itor and resume normal oscilloscope operation.

Mon-

3-2

2445/2465 Option 05 Operators

OPERATING CONSIDERATIONS

Section 4

Consult the oscilloscope Operators manual to acquire a
thorough understanding of the operation of the basic instru­ment before trying to use the features of the TV Option.
With the TV Option installed, all basic instrument functions
(as explained in the respective oscilloscope technical
uals) remain unchanged.

man-

FRONT-PANEL CONTROL AND SETUP

CONSIDERATIONS

The following information is useful when using the oscil-

loscope in TV applications.
oscilloscope front-panel controls and input signal
considerations.

TV Clamp

The TV (back-porch) clamp is used to stabilize ac­coupled TV waveforms and to remove tilt or hum present in
the displayed TV waveform. If the Channel 2 signal is not
composite video or composite sync or the sweep is not
gered on TV Sync, TV (back-porch) clamp operation is

unpredictable.

To

operate properiy, observe the

trig-

A-FLD LINE # Control

The A-FLD LINE # control is used for selecting a specific
TV line within a field as well as positioning the A cursor.
When it can be used for line numtjer selection, a delta (A)
symbol appears in the crt readout display following the line
number. If a delta symbol is not displayed, the control is
used to position the A cursor for the At, 1/At or AV func­tions.

The following two paragraphs describe how to switch
the function of the control from one to the other during a
series of measurements.

To enable the control to select a TV line when it is cur­rently controlling the A cursor, press the TRIGGER
PLING switch once. This will not change the current
coupling mode selected and the A symbol will appear in the
crt readout next to the line number.

If the control is currently controlling TV line number selec­tion and it is desired to make a At, 1/At, or AV measure­ment, press in the At button to get the At function, both the
At and AV buttons to get the 1/At
to get the AV function. The control can now be used to
position the A cursor.

function,

or the AV button

COU-

If the TV (back-porch) clamp is enabled with no TV sync

applied to the trigger, the CH 2 trace may drift vertically.

This is normal; turning the TV (back-porch) clamp off will

restore normal operation.

Use the procedure below to identify the signal type of an

input signal to the CH 2 input connector.

1.

Tum the TV (back-porch) clamp off and select CH 2

TRIGGER COUPLING.

2.

Obtain a stable waveform using the desired TV trigger

mode.

3. Determine whether the displayed signal is composite

video or composite sync.

4.

If necessary, turn the TV (back-porch) clamp on.

Slope Selection

When using the TV trigger, select the proper slope for
triggering on the TV
nals,

set the SLOPE switch to -. When triggering on sync-

positive displayed signals, set the SLOPE switch to

Display Considerations

The TV Option circuitry does not detect the color burst
phase or Bruch Sequence color burst blanking information.
In a four-field Pal Sequence with Bruch Sequence color
burst blanking, Fields 1 and 3 will be displayed when Field 1
is selected (odd fields), and fields 2 and 4 will be displayed
when Field 2 is selected (even fields). Qn noninteriayed scan
systems the TV Option detects start of field information

only. Field 1 and Field 2 are then two consecutive fields of
information.

signal.

For sync-negative displayed

4-

sig-

•

4-1

Operating Considerations
2445/2465 Option 05 Operators

MULTI-TRACE MODES. When using the TV trigger and
multi-trace operation, the trigger source must not be VERT
mode.

When only one trace is displayed, the VERT position

of the TRIGGER SOURCE switch may be used.

OVERSCANNED.DISPLAYS. For various video measure-

ments, it may be desirable to magnify the video waveform
vertically beyond the limits of the screen. Under these cir­cumstances, the trigger amplifiers or the option circuitry
may be overloaded, blocking out some sync pulses in the
vicinity of strong video transitions, or losing sync pulses al­together. To avoid overioad problems, use one of the other
vertical channels to supply a constant amplitude signal to
the option circuitry while the overscanned observations are
being made.

RF INTERFERENCE. Operation in the vicinity of some

FM and TV transmitters may contain objectionable amounts
of rf signal energy in the input signal, even when coaxial
input connections are used. The front-panel 20 MHz BW
LIMIT switch will usually eliminate such interference from
the display, but will not affect the signal reaching the option
circuitry. Where the rf interferes with option operation, ex­ternal filters will be required.

MULTIPLE-DISPLAYED WAVEFORMS. Within a given

frame,

the color burst alternates phase every line. Since
there are an odd number of lines per frame on interiaced
scan systems a given line within a frame will alternate color
burst phase between frames. This is readily apparent when
viewing a specific line within a frame. Understanding this
color burst phasing and how A and B sweeps are triggered
is important when interpreting multiple-displayed
waveforms.

Oscilloscope Dc Balance Routine

With the TV Option installed, the main instrument dc
ance routine can be accomplished with the CH 2 Input
pling switch in either the 1 Mfi AC position or the TV
CLAMP position.

Front-Panel Update

When any front-panel change is made and the TV (back­porch) clamp is enabled, the display may jump vertically.
However, the TV (back-porch) clamp will return the back­porch level to its previous position.

CH 2 SIGNAL OUT Connector

To preserve waveform fidelity of a video signal applied to
the CH 2 Input Connector when the TV Clamp is enabled,
the CH 2 SIGNAL OUT connector on the instrument rear
panel should be unterminated (open). If the connector is ter­minated into 50 fi, there may be a slight shift in the back­porch level between adjacent lines of the video waveform.

bal-

Cou-

IDENTIFYING FIELDS, FRAMES, AND

LINES IN 525/60 AND 625/50 TV SYSTEMS

NTSC (CCIR System M)

Field 1 is defined as the field whose first equalizing pulse

is one full H interval (63.5 ^s) from the preceding horizontal
sync pulse. The field 1 picture starts with a full line of video

and its lines are numbered 1 through 263, starting with the

leading edge of the first equalizing pulse. The first regular
horizontal sync pulse after the second equalizing interval is
the start of line 10.

Review the base instrument operators manual parts on
horizontal and delta measurements and delayed sweep
operation.

In A Alt B mode, the sweeps are displayed as follows: A
sweep, delayed (B) sweep, A sweep, delayed (B) sweep. In
this mode, if At mode is selected and Fid 1 or Fid 2 trigger is
selected,
sweep, A sweep, B sweep. Note that since B sweeps are
essentially "interiaced" with the A sweep, each A and B

sweep is triggered on every other frame. Since color burst
phase alternates on every frame, the A and B displayed
waveforms will each show one phase of the color burst

information.

triggered on every frame and the displayed waveform will
show txjth phases of the color burst.

sweeps occur in the following order: A sweep, B

If A only or B only sweep mode is selected, sweeps are

4-2

Field 2 starts with an equalizing pulse a half-line interval

from the preceding horizontal sync pulse. The field 2 picture
starts with a half line of video and its lines are numbered 1
through 262, starting with the leading edge of the second
equalizing pulse. After the second equalizing interval, the
first full line is line 9.

CCIR System B and Similar 625/50 Systems
(including PAL)

In most 625-line, 50-Hz field-rate systems, identification
of parts of the picture relies primarily on continuous line
numbering rather than on field-and-line identification, except
for PAL systems.

The CCIR frame starts with the first (wide) vertical sync
pulse following a field which ends with a half-line of video.
The first line after the second equalizing interval is line 6; the

Operating Considerations

2445/2465 Option 05 Operators

first picture line is line 23 (half-line of
the frame contains lines 1 through the first half of line 313,
and the picture ends with a full line of video (line 310).

The second field of the frame commences with the

ing edge of the first (wide) vertical sync pulse (middle of line

313),

and runs through line 625 (end of equalizing interval).
The first full line after the equalizing interval is line 318; the
picture starts on line 336 (full line).

The first field is referred to as
as "even". Note that the identification systems for System­M and System-B are reversed.

In the four-field PAL sequence with Bruch Sequence

Color-burst blanking, the fields are identified as follows:

Field 1: Field that follows a field ending in a half-line of

video,

when preceding field has color burst on the
last full line. Field 1 lines are 1 through 312 and half
of line 313. Color burst starts on line 7 of field 1; a
half-line of video appears on line 23.

video).

The first field of

"odd",

and the second field

lead-

Field 3: Field that follows a field ending in a half line when

preceding field has no color burst
Field 3 lines are 1 through the first half of line 313.

Burst starts on line 6 (immediately following the last
equalizing pulse); a half-line of video appears on
line 23.

Field 4: Field that follows a field ending in a full line carrying

color burst. Field 4 lines are the second half of line
313 through line 625. Color burst for field 4 starts
on line 320 (two full lines without burst follow the
last equalizing pulse); video starts with a full line on
line 336.

on

its last

full

line.

GPIB CONTROLLABLE FUNCTIONS

If the GPIB Option is installed in the instrument,
tional commands to control the TV Option via the GPIB are
available. The commands are listed in Table
the upper-case characters of a command are required for
recognition. See the GPIB Operators manual for additional

information relating to GPIB operation.

4-1,

addi-

and only

Field 2: Field that follows a field ending in a full line which

does not carry color burst. Field 2 lines are the last
half of line 313 through line 625. Color burst starts
on line 319 (one line without burst following the last
equalizing pulse); a full line of video appears at line

336.

When using the GPIB to set the field line number, the

option should be stably triggered on a valid composite video
or composite sync waveform. If it is not stably triggered, the

max line in the option may be set to a low number. An error

code may then result on the GPIB controller when an at­tempt is made to change the line numtjer to what is believed

to tje a valid line number over the GPIB.

4-3

Operating Considerations
2445/2465 Option 05 Operators

Table 4-1

GPIB Command Set for the TV Option

ATRigger

ATRigger?

TVClamp

TVClamp?

Header

Argument

coupling:

SLOpe:

coupling

SLOpe

QN

OFF

Argument

FLD1
FLD2
ALTemate
LINES

PLUS
MINUS

Comments

Selects TV option trigger mode from list.
These commands are in addition to the A

trigger commands used by the main

instrument.

Query returns: ATR COU:string, SLO:string;
where string is one of the respective
argument parameters.

Causes the CH 2 input coupling to be
switched to AC and the TV (back-porch)
clamp to be active.

If the TV (back-porch) clamp is enabled, the
CH 2 input coupling is switched to AC and
the TV (back-porch) clamp is turned off.
Othenwise, no change to the CH 2 input
coupling occurs.

Query retums either TVC ON or TVC OFF.

TVLine

TVLine?

LCNTStart

LCNTStart?

LCNTReset

LCNTReset?

ID?

<nrx>

PREFld

ATFld

FlOnly
BOTh

<nrx> is the TV line number chosen to

trigger the oscilloscope.

Query returns present line numtjer displayed.

Line count begins 3 lines before field-sync
pulse (System-M).

Line count begins at field-sync pulse
(Nonsystem-M).

Query returns Line 1 definition: either LCNTS
PREF or LCNTS ATF.

Line count is reset only on field 1 (Format 2).
Both field 1 and field 2 reset the line counter

(Format 1).

Query retums Line count reset status: either
LCNTR FIO or LCNTR BOT.

See the GPIB Option manual system
commands for details. The string returned for
the TV Option is TV:FVz where z is the
version number.

4-4

2445/2465 Option 05 Operators

BASIC APPLICATIONS

Section 5

The basic instrument with the TV Option provides an ac-

curate and flexible measurement system for displaying and

analyzing video information. After becoming familiar with the
controls, Indicators, operating considerations, and capabili­ties of the instrument, perform the following procedures to
become familiar with the oscilloscope functions for making

TV-related measurements.

Before proceeding with these instructions, refer to

"Preparation for Use" (Section 3).

Verify that the POWER switch is OFF (push button out);

then plug the power cord into the power outlet.

Initial Setup

a. Press in the POWER switch button (ON).

b. Set the instrument controls to obtain a baseline trace

as follows:
Vertical

CH 2 POSITION

MODE

BW LIMIT
CH 2 VOLTS/DIV
CH 2 VOLTS/DIV VAR
CH 2 Input Coupling

Midrange
CH2
Off (button out)

0.2 V
Calibrated detent
GND

c. Adjust the INTENSITY and READOUT INTENSITY
controls for desired display and readout brightness and best
trace definition.

d.

Adjust the Vertical and Horizontal POSITION controls

to position the trace within the graticule area.

Signal Input Coupling

This procedure demonstrates the appearance of a video
signal with the different positions of the

CH

2 Input Coupling

switch (see Figure 5-1).

Horizontal

A AND B SEC/DIV
SEC/DIV VAR

POSITION
XlO MAG

Trigger

HOLDOFF
LEVEL
MODE
SOURCE

COUPLING

SLOPE

Locked together at 5 ms
Calibrated detent
Midrange
Off (button out)

MIN (fully CCW)
Midrange
NORM
CH2
FLD1

- for sync-negative dis­played signals and 4- for
sync-positive displayed
signals

Figure 5-1. Appearance of video signal with CH 2 Input
Coupling switch positions.

5-1

Basic Applications
2445/2465 Option 05 Operators

a. Connect a composite video signal to the CH 2 input
connector and change the CH 2 Input Coupling switch to
DC.

b. Obtain a stable baseline trace.

c. With the CH 2 Input Coupling switch in 1 Mfi DC, note
that the signal edges are flat.

d.

Set the CH 2 Input Coupling switch to 1 Mfi AC and
note the tilt in the waveform due to the input coupling
capacitance.

e. Set the CH 2 Input Coupling switch to TV CLAMP.
Notice that the waveform no longer has tilt and has returned
to a dc-coupled appearance.

Time Interval Measurements

This procedure demonstrates how to use the At cursors

to make timing measurements on the video waveform.

a. Set the TRIGGER COUPLING switch to the UNES

position and the A AND B SEC/DIV switches to 10

MS.

e. Set the TRIGGER COUPLING switch to either FLD 1
or FLD 2, depending on which field the desired line is in. The
INTENSITY control may have to be adjusted to increase the

trace brightness.

f. Adjust the FLD LINE # control until the desired line
number appears in the crt readout. Specific time measure­ments on that particular line can now be made.

This procedure may also be used to measure the width of

a sync pulse.

g.

Set the CH 2 VOLTS/DIV, VAR, and POSITION
trols so that the sync pulse exactly fills the screen tjetween
the 0% and 100% graticule lines. Enable the At function,

push in the XlO MAG button, and position the sync pulse on
screen using the Horizontal POSITION control.

h. Use the A REF OR DLY control to position one cursor
at the 50% point of the leading edge of the sync pulse (at
the center horizontal gratiucle line) and use the A control to

position the other cursor at the 50% point of the trailing
edge of the sync pulse. The sync pulse width can now be
read directly from the upper-right corner of the crt readout.

con-

Voltage and IRE Measurements

b. Push in the At button.

c. Use the A REF QR DLY control to position one cursor
on the rising edge of the first sync pulse and use the A
control to position the other cursor on the rising edge of the
next sync pulse. The line interval period can now be read
directly from the upper-right corner of the crt readout. Qn a
525-line/60-Hz interiaced system, the readout should tje ap­proximately 63,4
should produce a readout of approximately 64,0 fis.

d.

Push in both the AV and At buttons simultaneously to
get the 1/At function. The crt readout now contains the line
interval frequency. Qn a 525-line/60-Hz interlaced system,
the readout should be approximately 15.8 kHz. A 625­line/50-H2 system should produce a readout of approxi­mately 15.6 kHz.

The preceding procedure measured line intervals on
those random lines of the video signal which triggered the
oscilloscope sweep. To make a time interval measurement

for a particular line within a

MS.

A 625-line/50-Hz interlaced system

field:

Voltage measurements can be made on the video signal
using the AV cursors and the crt readout. In addition, IRE
measurements expressed in percentages can also be made
and displayed on the crt as a percent.

a. Push in the AV button, set the X10 MAG button out
for X1 magnification, and return the CH 2 VOLTS/DIV VAR
control to its calibrated detent. Waveform voltage measure­ments can now be made by using the A REF OR DLY and A
controls to position the AV cursors at the desired points of
the video signal. The crt readout will correspond to the volt­age potential between the two points on the waveform.

b. Set the CH 2 VOLTS/DIV, VAR, and POSITION
trols so that the back porch and the top of a 100%­modulated video signal exactly fill the screen between the
0% and 100% graticule lines.

c. Any part of the waveform can now be measured in
IRE units by using the A REF QR DLY and A controls to
position the AV cursors at the appropriate positions of the
waveform. The crt readout will be a percentage which will

correspond with the IRE measurement units.

con-

5-2

MANUAL CHANGE INFORMATION

At Tektronix, we continually strive to keep up with latest electronic developments
by adding circuit and component improvements to our instruments as soon as they
are developed and tested.

Sometimes, due to printing and shipping requirements, we can't get these
changes immediately into printed manuals. Hence, your manual may contain new
change information on following pages.

A single change may affect several sections. Since the change information sheets
are carried in the manual until all changes are permanently entered, some
duplication may occur. If no such change pages appear following this page, your
manual is correct as printed.

n

•X

»

2

a

rr

2

T

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X

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2

l^ktronix® MANUAL CHANGE INFORMATION

COMMFTTED TO EXCELLENCE

nnto- ^'^ ^-84 fihangft Rftforcnrp- C2/0784

PrnH...f 2445/2465 OPT 05 OPERATORS

EFFECTIVE ALL SERIAL NUMBERS

M«n....

DESCRIPTION PG 38

TEXT CHANGES

Page 1-3 TRIGGERING

Add the following to the Performance Requirements for Sync Separation.

For noninterlaced scan systems, the video signal source must start and
end with full lines of video for correct line identification in the field trigger
modes.

Page 2-3 READOUT DISPLAYS

In the second paragraph, replace the first sentence with the following.

The crt readout will display TV Thgger information when the Trigger
COUPLING switch is set to any of the TV trigger modes
or LINES) and scale factors are on or when the TV (back-porch) clamp is
active and scale factors are on.

(FLD1,

FLD2, ALT,

P.rt Mn • 070-4629-00

Page 3-1

Add the following section.

FILTER/GRATICULE REPLACEMENT

The plastic filter or graticule over the crt faceplate can be removed by
sliding the filter or graticule up until the bottom edge is exposed. Pull the
bottom edge out and slide the filter or graticule down.

Page 3-2

Add the following line to part 8.

Push down once on the TRIGGER COUPLING switch.

Page 3-2

Add the following section.

AUTOMATIC SYNC SELECTION

Automatic sync selection is a feature which allows the user to preselect
the polahty of sync used most often. Automatic sync selection will change
the sync to the preselected polahty when the user enters a TV trigger
coupling selection. Once TV trigger has been activated the user may
change the polarity as
the TV option area will not cause the sync selection to be changed.

desired.

Changing trigger coupling selections within

000-2775-OOD

Page 1 of 2

Product- 2445/2465 OPT 05 OPERATORS

An exerciser (EXER 63) routine controls this function. The TV option can
be set up to automatically select the desired sync when entering the TV
trigger. There are three possible selections for exer 63:

POSITIVE: TV option will select sync positive when entering TV

trigger.

NEGATIVE: TV option will select sync negative when entering TV

trigger.

DEFSLOPE: TV option sync selection will default to the A trigger

slope,

(prior to this version MV2 DEFSLOPE has tjeen the only possible

selection)

Date:

7-16-84

DESCRIPTION

Change Reference:

C2/0784

After entering exer 63 the display will

TVSYNC:POSITIVE

OR

TVSYNC:NEGAT1VE

OR

TVSYNC:SLQPE DEFAULT

Selection Is controlled by the trigger coupling switch. An up push when
TVSYNC is POSITIVE will change the selection to NEGATIVE, the next up
push will change to DEFSLOPE, the next up push will return to POSITIVE.
A down push will exit exer 63 and store the last state displayed. Push the
A/B TRIG button to exit the diagnostic monitor.

read:

Page 4-1 Slope Selection

Replace the Slope Selection paragraph with the following.

When using the TV trigger, the A trigger slope controls the polarity of sync

on which the option will trigger. For sync-negative displayed signals, set the
slope to -. When triggering on sync-positive displayed signals, set the

slope to 4-.

Page 4-4 Table 4-1

Add the following command to the table.

Header

TVSync

001-0057-OOD

Argument

POSITIVE

NEGATIVE

DEFSLOPE

Argument

Comments

Sync is set to positive when activating the TV
trigger.

Sync is set to negative when activating the TV
trigger.

Sync defaults to the present value of the A trigger
slope when activating the TV trigger.

Page 2 of 2