SL5162
Multistandard VHF and UHF Television Demodulator
Supersedes September 1996 edition, DS4497-2.1
DS4497-3.0 September 1998
The SL5162 multistandard modulator up-converts a
baseband video signal with separate audio frequency input
on to a VHF or UHF carrier up to 860MHz. It provides RF
signals with negative or positive video modulation and AM
or FM sound subcarrier to satisfy both PAL/NTSC and
SECAM applications.
The on-chip local oscillator uses an external resonator
tank which may be controlled via any Mitel 1.3GHz
synthesiser. Selection of both video and sound standards
are provided by level switching of a single pin.
A video AGC circuit is provided to ensure constant
modulation depth. In PAL mode this may be disabled and
a white clip circuit switched in to prevent overmodulation if
desired.
RF1
RF2
V
CC
2
LOIN1
LOOP1
LOOP2
LOIN2
V
EE
2
ST1
ST2
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
AGC
VIDEO
TSG
V
EE
1
OP2
OP1
MSS
SUB2
V
CC
1
AUDIO
SL5162
15
14
13
12
11
MP20
FEATURES
s
Covers both Negative and Positive Modulation Sys-
tems
s
Internal AGC with Disable
s
Control of Sound and Video Standard via Single Pin
s
Symmetrical 75Ω RF Outputs for Low Radiation
s
Audio Input with AM/FM Sound Modulator
s
Switchable Video Test Signal Generator (TSG)
s
Intercarrier Input for Second Sound Channel
s
ESD Protection
PRESCALER OUTPUTS
5
6
Figure 1 Pin connections – top view
ORDERING INFORMATION
SL5162/KG/MP1S
Miniature plastic package
SL5162/KG/MP1T
Tape and reel
ABSOLUTE MAXIMUM RATINGS
Storage temperature
Junction temperature
Ambient temperature
Supply Voltage
Voltage at any other pin
255°C
to1150°C
220°C
to1150°C
210°C
to180°C
20·3V
to17·0 V
20·3V
to17·0V
UHF
OSC
1
2
UHF
MIXER
15
16
UHF
TANK
4
7
MODULATED
OUTPUTS
SUBCARRIER 2
13
FM
CLAMP
AUDIO OSC
AGC
MIXER
DRIVER
FM/AM
SELECT
9
10
VIDEO
INPUT
75
19
SOUND
TANK
11
20
AUDIO
INPUT
MODE
SELECT
TSG
AGC
CLIP
OFFSET
ADJUST
14
CLIP
TSG
ENABLE
18
LOGIC
Figure 2 Block diagram
SL5162
ELECTRICAL CHARACTERISTICS
T
AMB
=
125°C
(operating range
210°C
to180°C), V
CC
=
15V,
(operating range14·5 to15·5V). Max and Min values are
guaranteed by either production test or design. They apply within the specified temperature and supply voltage ranges unless
otherwise stated.
Characteristic
Supply Voltage
Supply current
Video Input
Video input level (V
P
)
Eff. white clip level (V
C
)
Input impedance
Video bandwidth
21
dB
23dB
Video SNR weighted
Differential gain
Differential phase
Line tilt (black level)
Clamp accuracy
Audio Input
Input impedance
Audio bandwidth (21dB)
Subcarrier frequency
FM THD
Intercarrier Input
Input level
FM Performance
Audio input for 100%
deviation (635kHz)
FM deviation sensitivity
Max frequency deviation
AM Performance Audio
Modulation depth
Audio SNR (wideband)
RF Output
Peak vision carrier:
SECAM (L)
PAL
Flatness band 470-860MHz
APLD
White Level, Nominal
Negative modulation
Sync Tip
Negative modulation
Positive modulation
Sync degradation (1ve mod)
Pin
Min.
3, 12
3, 12
19
4·5
45
1·0
0·5
1·17
100
10
25
60
1·5
Value
Typ.
Max.
5·5
53
V
mA
Vp-p
Vp-p
V
k
Ω
MHz
MHz
dB
%
deg
%
mV
k
Ω
kHz
MHz
%
V
P
= sync to white level, AGC disabled (note 1)
V
P
= sync to white level, AGC enabled
V
C
= sync to limit level (note 2)
Except for duration of clamp pulse
Units
Conditions
62
62
62
CCIR Rec 451-1 (note 3), mono sound system
65
65
0·5
5
Dependent upon video input clamp capacitor
V
P
=1·0V
D
(black level with and without input video)
11
25
15
4
0·5
13
140
11
100
0·7
250
11
80
.46
1, 2
83
84
2
62
1, 2
12
1,2
100
6
1
%
%
%
All systems
D
SYNC
1(16
S
3
7
3100)
W 3
17
22
%
Relative to peak vision carrier (PVC), V
P
= 1·0V,
all systems (note 4)
dBµV
V
P
= 1·0V, sync = 0·3V
dBµV
Differential 75Ω output
dB
%
APL 10-90%
%
dB
Input = 200mVp-p at 1kHz
mVp-p
At device input
kHz/mV
Audio input 1kHz sinewave
kHz
No pre-emphasis, dependent on external
components
mVp-p
To define
222dBC
(peak carrier)
7
1·0
Determined by external components.
In demodulated signal. Input signal =1 kHz sinewave
at
635kHz
deviation
NOTES
1. This is the nominal input level to provide the preset video modulation index for the selected standard. Any variation from the
nominal level will change the RF modulation index.
2. The actual clip level is set relative to the input video level. The level of 1·17V only applies if the video input signal is correctly
proportioned. The white clip circuit operates only when the AGC is disabled.
3. Measured at CH38 with R&S EMFP demodulator and UAF Video Analyser.
4. Measured at CH21 with R&S EMFP reference demodulator and UAF Video Analyser. Synchronous demodulation.
2
SL5162
ELECTRICAL CHARACTERISTICS (continued)
Characteristic
Pin
Min.
Mod Index Control
Sound subcarrier level,
negative video modulation
Sound subcarrier level,
positive video modulation
Second sound subcarrier
Video Test Sig. Generator
18
Negative impedance
Ceramic resonator impedance
Prescaler
1, 2
Output amplitude
Distortions
Intermodulation:
f
V
1(f
S
2f
C
)
f
V
12f
C
f
V
12f
S
f
V
13f
S
Spurious (in band)
Spurious (ex band)
Harmonics:
2f
V
3f
V
Sound in vision
Vision in sound
Local Oscillator
4,5,6,7
Frequency range
Residual FM
Value
Typ.
Max.
Units
Conditions
216
215
222
23
500
30
dBC
dBC
dBC
k
Ω
Relative to PVC (note 4)
Relative to PVC, with no audio modulation applied
Relative to PVC
mVp-p Single ended from 50Ω
Values referred to PAL system G carrier level
Note 5
270
270
270
275
270
270
210
210
260
246
38·9
860
0·2
dBC
dBC
dBC
dBC
dBC
dBC
dBC
dBC
dBC
dBC
MHz
kHz
Relative to 83dBµV modulated carrier (note 6)
With 1Vp-p video input signal colour bars
NOTES
5. f
V
= vision carrier, f
S
= sound subcarrier, f
C
= chroma subcarrier.
6. SUB 2 must be connected to V
CC
to achieve this performance.
Pin
1
2
3
4
5
6
7
8
9
1o
11
12
13
14
15
16
17
18
19
20
Name
RF 1
RF 2
V
CC
2
LOIN 1
LOOP 1
LOOP 2
LOIN 2
V
EE
2
ST 1
ST2
AUDIO
V
CC
1
SUB 2
MSS
OP 1
OP2
V
EE
1
TSG
VID
AGC
Function
UHF prescaler output 1
UHF prescaler output 2
Positive supply for UHF circuits
UHF tank
UHF tank
UHF tank
UHF tank
UHF ground
Sound tank 1
Sound tank 2
Audio 1 input
Positive supply for baseband circuits
Intercarrier (sound) input
Video modulation/standard select
75Ω modulated output
75Ω modulated output
Baseband ground
Test signal generator input
Video input
AGC capacitor/disable switch
VIDEO INPUT SECTION
A composite signal of the selected standard is applied to
the device via a coupling capacitor also acting as the clamp
storage capacitor. A minimum level clamp is used to DC
restore the video signal in the IC to an internally defined
reference voltage.
The AGC will give a constant output level with input signals
between 0·5 and 1·5 Vp-p. If a controlled 1Vp-p video signal
is available, the AGC may be disabled, in which case a white
clip circuit is switched in, to prevent possible overmodulation.
Selection of negative or positive modulation is via a single
pin (14). The voltage on this pin controls an offset which is fed
to the UHF mixer, thus determining both modulation depth,
and sense of modulation.
SOUND SECTION
The sound is AC coupled and AM or FM modulated onto
the pre-selected carrier, 4·5 - 6·5MHz; its level is nominally at
216dB
relative to the peak vision carrier.
UHF MODULATED OUTPUT
Modulation and relative levels of vision and sound carrier
levels are preset for the selected broadcast standard.
Table 2 gives the output options available. Modulation index
is fixed at 83% for all negative modulation systems and at 94%
for SECAM standard L. Selection of sound tank frequency is
defined by off-chip tank components.
Table 1 Pin descriptions
3
SL5162
Standard
NTSC (M)
PAL (G)
PAL (I)
SECAM (L)
Negative
Negative
Negative
Positive
Video
Modulation
Mod. index (%) SC freq. (MHz)
83
83
83
94
4·5
5·5
6·0
6·5
Sound
Modulation
FM
FM
FM
AM
Pre-emphasis (
µ
s)
75
50
50
Through
Table 2 Video modulation/standard selection
TEST SIGNAL GENERATOR (TSG)
The internal test signal generator is driven from a 500kHz
ceramic resonator. The TSG waveform is shown in Figure 3
and has an effective input video amplitude of 1V sync tip to
white. Note that when TSG is enabled, the sound subcarrier
modulation is disabled and so the audio is muted.
64µs
WHITE
Modulated Outputs
The routing of the modulated outputs requires special
attention since these are particularly vulnerable to coupling
from the VCO: unwanted coupling of the LO frequency to the
RF output will modify the modulation depth. Typically, in
instances where RF coupling is present, the amount of
coupling (and the phase) will vary as the oscillator is tuned
across the band, causing the modulation index to be either
higher or lower than the situation where no RF coupling is
present. Thus the modulation index will vary as the device is
tuned from one channel to another. For VHF and other
applications below 500MHz, oscillator coupling is not such an
issue, however similar care should still be taken with the
layout in order to maximise device performance.
4
µs
20
µs
4
µs
12
µs
4
µs
20
µs
BLACK
Use of a Balun
It is possible to further improve device performance with
the use of a balun to remove the effects of common mode
coupling. Although using a balun will add to component cost,
it may be the best way to achieve maximum performance at
higher frequencies where common mode noise has made it
impossible to achieve the required SNR or dynamic range in
the output signal. A low cost balun wound on a ferrite bead
former should be sufficient to provide adequate performance
in the majority of applications.
SYNC
Figure 3 TSG waveform
APPLICATION NOTES
The key to achieving acceptable modulator performance is
to ensure a well planned circuit layout with good RF decoupling
of all supplies and sensitive pins. Ground loops should be
avoided or kept as small as possible since RF coupling is the
single most important characteristic in degrading modulator
performance. Where possible, double sided board with a
ground plane should be used and care taken to decouple all
sensitive pins as close to the device as possible.
Sound Tank Circuit
It is recommended that the sound tank shown in Figure 4
is used. For PAL G, NTSC or SECAM applications, the value
of the inductor may be modified to achieve the required
subcarrier frequency. The tank circuit can be tuned between
4MHz and 7MHz. The sound subcarrier is automatically gain
controlled to a value which gives a 16dB picture-to-sound
carrier ratio when the SL5162 is set to negative modulation.
The audio input signal is AC coupled through pin 11. The FM
sensitivity of the of the sound section is 0·7kHz/mV, therefore
a 140mVp-p input signal should give a
650kHz
deviation of
the sound subcarrier.
Oscillator Design and Layout
The oscillator layout should be kept as small as possible
to minimise parasitics. It is also recommended that the ground
plane is kept as far away from the oscillator itself since this will
minimise the unwanted capacitance from the tank components
to the ground plane. This has two advantages:
1. It increases the oscillator tuning range
2. It minimises the amount of RF coupled into the ground
plane by the oscillator.
The circuit diagram shown in Figure 4 can be used for UHF
or VHF applications. Surface mount components should be
used wherever possible since these will minimise parasitics
and also allow a more compact circuit design. For applications
at VHF the values of the tuning components must be modified:
the coupling capacitors should be increased to a value of
2·2pF or greater. For fixed frequency applications up to
100MHz (or limited tuning range applications) 15pF coupling
capacitors can be used. Varactor tuning of the SL5162 should
not be attempted unless the oscillator is synthesised, due to
the wide temperature variation of varactor diodes. The
application shown in Figure 4 uses a Mitel 1.3GHz TV
synthesiser. This provides the required stability and tuning for
the VCO. Any of the of the Mitel Media Products I
2
C and 3-wire
bus synthesisers such as SP5611, SP5502, SP5026 should
be suitable for use with the SL5162
Stereo Sound
For stereo applications, a previously modulated second
subcarrier should be input via the SUB 2 input (pin 13). For
example, with the German Panda system, this would normally
be at 5·74MHz. An input level of 200mV p-p should provide
the required picture carrier/sound carrier ratio of 22dB.
Video Modulation/Standard Selection
The SL5162 may be switched between negative and
positive modulation standards via MSS, pin 14. This configures
both the sense of video modulation (negative or positive), and
switches the modulation on the sound subcarrier to AM when
positive video modulation is selected. These standards are
switched as shown in Table 3. To ensure reliable startup over
the entire V
CC
range it is recommended that the sound tank
circuit is started via an effective pulse from the I
2
C bus
synthesiser used in the system. This is shown in the demon-
stration board circuit, Figure 4. To do this, one of the
4
Making friends through disassembly
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