IS 4545-2: Methods of Measurement on Receivers for Television Broadcast Transmissions, Part 2: Tuning Properties and General Measurements

2008·1.2 MB·English

by  Bureau of Indian Standards

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IS 4545-2 (2008): Methods of Measurement on Receivers for
Television Broadcast Transmissions, Part 2: Tuning
Properties and General Measurements [LITD 7: Audio, Video
and Multimedia Systems and Equipment]
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IS 4545 (Part 2) :2008

( w XT?W
)
Indian Standard
METHODS OF MEASUREMENT ON RECEIVERS FOR
TELEVISION BROADCAST TRANSMISSIONS
PART2 TUNING PROPERTIES AND GENERAL MEASUREMENTS
Second Revision)
(
ICS 33.160.020
@ BIS 2008
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

June 2008 Price Group 3
Audio, Video and Multimedia Systems and Equipments Sectional Committee, LITD 07
FOREWORD
This Indian Standard (Part 2) (Second Revision) was adopted by the Bureau of Indian Standards, after the draft
finalized by the Audio, Video and Multimedia Systems and Equipments Sectional Committee had been approved
by the Electronics and Information Technology Division Council.
The object of this standard is to lay down the general conditions of measurements to be used for testing of a
receiver for television so as to make possible the comparison of the results of measurements. Limiting values of
the various quantities for acceptable performance are not specified in this standard but would be covered in
separate standards.
The first version of IS 4545 which was published in 1968 covered the methods of measurement for television
broadcast receivers having monochromes vision reception. With the introduction of colour television receivers,
this standard was first revised in 1983 to make it applicable to receivers designed for both monochrome and
colour vision receptions and published in a number of parts to deal with different aspects of characteristics of
television receivers. Now, this revision is being undertaken to align the standard with the latest international
practices dealing with methods of measurement on television receivers as given in IEC 60107-1:1997 ‘Methods
of measurement on receivers for television broadcast transmissions — Part 1:General considerations’.
The other parts in this series are as follows:
Part 1 General considerations
Part 3 Geometrical properties of the picture
Part 4 Synchronizing quality
Part 5 Sensitivity
Part 6 Selectivity and response to undesired signals
Part 7 Fidelity
Part 8 Compatibility with audio visual recording equipment
Part 9 Electrical and acoustic measurements at audio frequency
Part 11Measurement under conditions different from broadcast signal standards
Part 12Electrical measurements on multi-channel sound television receivers using the NICAM two channel
digital sound system
This standard is largely based on IEC 60107-1:1997. This standard shall be read in conjunction with IS 4545
(Part 1): 2007.
For the purpose of deciding whether a particular requirement of this standard is complied with, the final
value, observed or calculated, expressing the result of atest or analysis, shall be rounded off in accordance with
IS 2:1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the
rounded off value should be the same as that of the specified value in this standard.
IS 4545 (Part 2) :2008
Indian Standard
METHODS OF MEASUREMENT ON RECEIVERS FOR
TELEVISION BROADCAST TRANSMISSIONS
PART2TUNING PROPERTIES AND GENERAL MEASUREMENTS
(Second Revision)
1SCOPE of the minimum tuning step is obtained by measuring
the local oscillator frequency and activating the fine
This standard (Part 2) covers methods of measurement
tuning procedure, following the manufacturers
i-elating totuning properties of the television receivers,
instruction.
namely:
a) Tuning methods, 3.2 Methods of Measurement
b) Tuning sensitivity,
3.2.1 Measuring Conditions
c) Automatic frequency control (AFC)
a) Video test signal : Composite test pattern
performance characteristics,
signal
d) Operating frequency and its stability,
e) Fine tuning frequency range, b) Audio test signal : 1kHz sine wave
f) Mechanical properties of tuning system, and c) Input signal : r.f. television signal with
g) Performance characteristics of presettable sound carrier(s)
tuning systems.
d) Test channels : Representative channels
2REFERENCES [see 9ofIS4545 (Part 1)]
The following standards contain provisions, which e) Input signal level: Standard input signal .4
level [see 3.2.1 of
through reference in this text constitute provisions of
IS 4545 (Part 1)]
this standard. At the time of publication, the editions
indicated were valid. All standards are subject to
3.2.2 Measurement Procedure (Standard Method)
revision and parties to agreements based on this
standard are encouraged to investigate the possibility a) Apply the r.f.television signal of atest channel
0’
of applying the most recent editions of the standards tothe receiver and tune itaccording to4.2.3.2
indicated below: of IS 4545 (Part 1).
b) Measure the local oscillator frequency when
IS No. Title
the input channel is applied at the nominal
4545 (Part 1) : Methods ofmeasurement onreceivers frequency. This is the nominal value of the
2008 for television broadcast transmissions: local oscillator frequency.
Part 1General considerations
c) Activate the fine-tuning procedure and get the
9000 (Part 1) : Basic environmental testing procedures
minimum step.
1988 for electronic and electrical items:
d) Measure the new local oscillator frequency
Part 1General
and calculate the difference with respect to
IS 12552: 1999/ Sound and television broadcast recei-
the nominal value measured in (b) above. This
CISPR 20:1998 vers and associated equipment —
is the minimum frequency step.
Immunity characteristics — Limits
and methods of measurement 3.2.3 Measurement Procedure (Alternate Method)
3TUNING METHODS In order to obtain better accuracy, the fine tuning
procedure [see 3.2.2(c)] is activated several times,
3.1 Introduction
measuring each time the local oscillator frequency [see
When the receiver tuning is provided by means of a 3.2.2(d)] and calculating the difference with respect
frequency synthesizer fine-tuning steps (that is also to the nominal value. Then each of these frequency
the minimum frequency step) depend on the design differences isdivided by the related number of applied
‘offrequency dividers and are all identical. The value steps of the fine tuning.

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1S4545 (Part 2) :2008
If the frequency measurement is sufficiently accurate 5.2.1 Measuring Conditions
(better than 1kHz) the calculated values are all identical
The same as those specified in 3.2.1.
and can be assumed tobe the minimum frequency step.
Otherwise, the minimum frequency step is obtained 5.2.2 Measurement Procedure (Standard Method)
by averaging the values calculated above.
a) Apply the radio frequency (r.f.) television
3.2.4 Presentation of Results signal of a test channel for which the carrier
frequencies are set atthe nominal frequencies
The results are presented as the value (kHz) giving the
and tune the receiver correctly. If anAFC on/
minimum frequency step.
off switch and a fine tuning control are
provided, first turn the switch off and tune
4TUNING SENSITIVITY
the receiver with the fine tuning and then turn
4.1 Introduction the switch on again. Then measure the
frequency of the local oscillator with AFC and
The tuning sensitivity is the extent by which the
calculate the intermediate frequency (if.),
receiver tuning may deviate from the correct condition
which is the difference between the local
ih order to give rise to ajust noticeable effect on the
oscillator frequency and the vision carrier
picture or on the sound.
frequency.
4.2 Methods of Measurement This if. frequency is used as the reference
if. in this measurement.
4.2.1 Measuring Conditions
b) Increase the vision carrier frequency
Same m Ihose specjf]ed in 3.2.1. gradually while measuring the local oscillator
frequency.
4.2.2Measurement Procedure
c) Continue (b) above and note the variations of
a) Apply the r.f.television signal of atest channel the vision carrier and local oscillator
tothe receiver and tune itaccording to 4.2.3.2 frequencies at several points until the control
of IS 4545 (Part 1). function of the AFC is lost. This point
b) Detune the frequencies of the vision and corresponds to the upper limit of the hold-in
sound carrier(s) of the channel gradually but range. Then calculate the if. frequencies at
tothe same extent until ajust noticeable effect these points.
on the picture or on the sound is obtained. d) Calculate the frequency control errors from
c) Measure the vision carrier frequency and the differences between the if. frequencies
calculate the difference from the starting and the reference if. and plot a curve
frequency. (see Fig. 1).
d) Repeat (b) and (c) above detuning the carrier e) Then decrease the vision carrier frequency to
frequencies in the opposite direction to that get AFC control function again and note the
done in (b). variation of the carrier frequency, which is
the upper limit of the pull-in range. Measure
4.3 Presentation of Results
the local oscillator frequency and calculate
The results are presented in a table showing the the if. at this point to obtain the frequency
frequency differences for each test channel. control error.
f) Decrease the vision carrier frequency from
5 AUTOMATIC FREQUENCY CONTROL
the nominal value and measure the lower
PERFORMANCE CHARACTERISTICS
limits of the hold-in and pull-in ranges in a
similar manner (see Fig. 1).
5,1 Introduction
5.2.3 Measurement Procedure (Alternate Method)
This test measures pull-in and hold-in ranges of alocal
oscillator ”with AFC by varying the vision carrier If an AFC on/off switch and fine tuning are provided
frequency of the input signal. If it is not possible to for the receiver, the AFC characteristic can be obtained
vary the vision carrier frequency, the measurement can by varying the local oscillator frequency with the fine
be made by changing the local oscillator frequency. tuning (see Fig. 2).
5.2 Method of Measurement In this case, the following procedure shall be used:
The local oscillator frequency can be measured in the a) Set the local oscillator to the free-running
same way as described in 6.2. mode by switching off the AFC and tune the

2
IS 4545 (Part 2) :2008
Frequency
“l-
error
. . .. .
‘s ——---
--+
1\ —_-. __, -b —--- --
* +
l\
\
~.
I
1-
&ho]d-inranqe &pull-in
FIG. 1AFC CURVEFORVARIATIONOFVISIONCARRIERFREQUENCY(CONCEPTUALDIAGRAM)
Oscillatior
freqwmcy +
-a —
l--
k- ‘b-— ,
.
,’
, i
,’
, !~
+’
,
,“
/
.’
.
,
.
,
>
Free runnin~
frequency
..’
.
,
.
“
a: hold-in range b pull-in range
FIG.2 AFC CURVEFORVARIATIONOFLOCALOSCILLATORFREQUENCY(CONCEPTUALDIAGRAM)

3
IS 4545 (Part 2) :2008
receiver with the fine tuning. Then turn on If an AFC is provided for the receiver, the
the AFC; measurements are carried out with the AFC.
b) Increase the local oscillator frequency by the
6.2 Method of Measurement
fine tuning control and find the higher limit
of the hold-in range. Then measure the local The frequency of a local oscillator can be measured
oscillator frequency variation with AFC atthis by a leakage voltage of the oscillator appearing at the
point and also measure the corresponding antenna terminal, ifaspectrum analyzer with frequency
free-running frequency variation by turning counting function is connected to the terminal.
off the AFC; Arrangement of the test equipment is shown in Fig. 3.
c) Then decrease the frequency by the fine
6.2.1 Measuring Conditions
tuning and measure the local oscillator
frequency variation with AFC and the Same as those specified in 3.2.1.
corresponding free-running frequency
6.2.2 Measurement Procedure
variation without AFC at the higher limit of
the pull-in range in the same way; and a) Apply the r.f. television signal of a channel
to the receiver. If the AFC is not provided,
d) Measure the frequencies with and without
tune the receiver correctly in accordance with
AFC at the lower limits of the hold-in and
the criteria defined in 4.2.3 of IS 4545 (Part
pull-in ranges in a similar manner.
1)when operation ofthe receiver isstabilized.
5.2.4 Presentation of Results
b) Turn off the power switch and allow the
The results are presented graphically orin atable giving receiver to cool to the room temperature.
the higher and lower hold-in and pull-in ranges relative c) Turn on the power switch and measure the
to the nominal frequency and corresponding if. errors frequency of the local oscillator in the period
or local oscillator frequency variations with AFC at between 1min after start and the time when
these points. the frequency is almost stabilized.
d) Then measure the frequency when the power
6OPERATING FREQUENCY AND ITS supply voltage is changed to the limits of the
STABILITY specified range.
e) If an AFC on/off switch is provided, repeat
6.1 Introduction
(b) to (d) above without AFC.
This test establishes the operating frequency of the i) Repeat (a) to (e) above for other channels.
receiver and its stability by measuring the local
NOTE—Unlessspecified bythe manufacturer, the limit should
oscillator frequency and its variations due to the
be ~iOpercent of the rated voltage.
operating period and supply voltage of the receiver at 8’
6.2.3 Presentation of Results
the specified television channels. Itis assumed that the
variation of the operation frequency is mainly due to The results are presented graphically asdeviations from
the variation of the local oscillator frequency. the starting frequency. Examples are shown in Fig. 4.
1 1 Antenna r 1
I
RF television
{
Signal Source
K5EE1-d “’’”t
I ‘/-
Spectrum
analyzer
FIG.3 ARRANGEMENTOFEQUIPMENTFORMEASURINGLOCALOSCILLATORFREQUENCIES

4
IS 4545 (Part 2) :2008
Frequency
Test channel No.2
variation
Ambient temperature 20 “C
kHz
(‘1
+60
+40
+20
0
-20
-40 —t-l-r -..
II I I I 11111 I
-60
1 1 1 1 f I I I I I
1 2 3 5710 20 30 50 70 100
T/me, min
Frequency
variation
Testchannel No,2
kHz
Ambient temperature 20 ‘c
+150
+100
+50
AFCon
0 ___ -“---
/ ~.
.-”
/’
/
-50
AFC off
-1oo
-150
80 90 100 110 120
MaInsvoltage, V
FIG.4 EXAMPLEOFOPERATINGFREQUENCYSTABILITY

5