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signal turns off the inverter (T 2317, T 2318) so thatthe driver
T 2320 is operative. The signal is not inverted, therefore, and:is fed
to contact 2. If a HIGH level is applied to contact 3 (selected by
button VIDEO) the signal is. inverted. The selected signal is then
applied at the same _ time to both capacitors C 2329
and C 2324.
From there, the signal is passed on via the switchable and
memorizable de-emphasis (button DEEM d1 = CCIR, d2 = D2MAC)
and an amplifier following to contact 2 of the 2-pin plug. Selection of
the de-emphasis (LOW. = CCIR; HIGH = D2MAC) takes place via
contact
10 of the module. The
de-emphasis
button
has two
functions:
first, changing
the audio de-emphasis
from
62ys
(50/75p1s) to J17 and second, changing the video de-emphasis from
PAL to D2MAC (d1 = PAL; d2 = D2MAC). The switchable feedback
circuit at the emitter of transistor T 2339 compensates for the
_ different amplitudes from transmitters with differing video frequency
deviations. To accomplish this, the transistor T 2346 Is. Controlled
via cones Guten VIDEO).
ee
ke
Signal Path in the Video Module
Video signal path
|
Pin 1 of the video plug-in board i is sible with the sncinplt ied base:
band signal. The transistor T 9200 acts as an impedance converter
with the video de-emphasis F 9202 and R 9202 following. The signal
is passed through transistor T 9203 to amplifier transistor T 9202.
After frequency correction — 5.8 MHz sound trap — the amplified
signal is fed to the video driver transistor T 9220. From pin 11 of the
plug-in board the signal passes the two video output stages T 745
and T 746 (chassis) and is supplied to the corresponding EURO-AV.
socket. The transistor T 9223 is the video signal decoupling stage
to the modulator. The decoupled signal is also applied to pin 2 of IC
9240 where it is amplified. Afterwards, the peaks of the black
signals — the envelope of which corresponds to a-25 Hz. energy
dispersal. signal — are rectified by diode D 9254. From this signal
the line-frequency components are eliminated in 1C 9240. The
resulting signal is amplified and passed through. the impedance
converter transistor T 9240 and fed to the emitter of the input:
amplifier T 9207 in opposite phase (base). The
energy dispersal
effect is thus compensated for. The switth NW
on the chassis
—
allows to switch the clamping: « circuit on or off via contact 4 of the
plug-in board. —
Sound signal path 3
From. the collector of transistor T 9200 the sound sional is ee via L
9222, C 9223 to contact 6 of the video plug-in board anid passed on
via C 331, C 324 to the input of IC 320 (sound mixer). The mixing
oscillator in IC 320 is subject to PLL control. The frequency range—
_
which has been extended from 5-8 MHz to. 5-8.5 MHz during the
series production — is mixed via the F 317 oscillator to the sound IF
of 10.7 MHz and fed to the sound-IF plug-in board. The integrated.
circuit IC 300 is the actual PLL which allows to tune the 5-8.5MHz
audio signal range in steps of 10 kHz. The pins 12, 13 and 14 are
supplied with the CLOCK, DATA and ENABLE signals coming from
the processor IC 100. The pins 13 and 15 of the sound-IF plug-in
board are provided as inputs for the mixed sound IF signal. On
satellite reception,
different sound
carrier frequencies can be
present there. These carriers are: the main carrier exclusively, the
main carrier and up to five subcarriers for different languages, the
"Mono" main carrier , two subcarriers with "Left* and "Right" AF
information: The high-deviation
main carrier is fed via the ceramic
filter Q 2206 to pin 14 of IC 2270. This IC is a limiting amplifier and
coincidence demodulator. On output at 8 two eee
sans
and Jt 7 standard are isha
,
Sound
Carriers
for
Different. Languages
or
Left-
Channel! Stereo
From the filters F 2202, F 2221 and F 2222 (10. 7 MHz) the sound
subcarrier with small deviation is applied to pin 14 of IC 2210. The
resulting AF signal from the limiting amplifier and coincidence
demodulator is fed via pin 4 to the de-emphasis following.
Right-channel stereo sound
carrier. The frequency level of
the right-channel stereo sound carrier in the baseband is 180 kHz
higher and its inverted frequency exactly the same amount lower,
i.e. on 10.52 MHz, than the left-channel stereo sound carrier. This
right-channel stereo sound subcarrier is fed via the filters F 2201, F
2212 and F 2211 to pin 11 of IC 2210. The AF signal resulting from
the limiting amplifier and coincidence demodulator is supplied via
pin 5 to the de-emphasis following. From the two de-emphasis
stages the AF signal is passed to pin 2 and pin 13 of IC 2250 (LM
1894)that acts as a dynamic noise reduction system abbreviated
DNR.
The AF signals then reach
a variable lowpass each -
consisting of two operational amplifiers to be passed on to pin 4 and
pin 11. These lowpass
filters
vary
the amplitude
response
according to the input level and frequencies. Low input levels cause
the filters to lower the high frequencies accordingly. A control path
between pin 8 and pin 9 includes a filter in order to avoid interfering
signals, eg. line-frequency components, influencing the system.
The AF signals are output on pin 4 and pin 11 and pass through two
voltage dividers to arrive at an electronic switch, IC 2280 (CD 4052)
which is also the receiving point for the signals from the carrier
demodulator with the two de-emphases. The required signals can be
selected and stored by means of the buttons AU DIO and DEEM.
Antenna and polarization selection
With the GRUNDIG Satellite Receiver signals can be received from
one or two parabolic antennas' which are directed to different
satellites. A single cable or two cables can be used to feed the
differently 'polarized signals. In the normal case, one antenna and
two cables are
employed and selection is indicated by the LED
display H1 or V1. Another possible way is to connect a polarizer.
With such a polarizer switchover is effected by selecting the same
signals as are used with individual down converters (LNCs). The
| selection can be stored. A Pin Diode switch in the tuner selects the
X or Y direction of reception. If it is not possible to lay out two
_ cables to the receiver a coaxial cable relay operating on a OV/12V
supply which can be tapped on the rear of the receiver (G9) see
Operating Instructions) is to be used to select the X or Y direction
on the parabolic antenna. This is also valid when two antennas are
used. In this case, the relay selects the wanted antenna. For this
purpose, a clamp is to be used to tap the necessary high-
impedance output voltages on thet rear of the receiver meaning:
OV = antenna 1 horizontal
Display
#1
3V=antennalvertical
V1
6V = antenna 2 horizontal —
.
H2
9V = = = antenna 2 vertical
|
V2
Adjustment of the polarizer
-
Set the "X polarizer' regulator on the bottom of the receiver to
_ mechanical mid-position.
-
'Tum and secure the LNC to yield optimum reception of
| horizontally polarized signals eg. RA! 1 followed by fine
adjustment of the TV station by means of the X regulator while
simultaneously checking the AGC on pin (19) see Operating
_ Instructions) on a measuring instrument.
-
The reception of vertically polarized signals, eg. Tele Club, is
adjusted with the "Y polarizer" regulator. The position of the LNC
must not be changed any more.
The infra-red Telepilot RC 200 can be used for remote control of all
programme
locations. The button "0" switches the receiver to
"standby" mode during which the operating voltage for the wide
band amplifier i in the modulator is not switched off. Video operation
via RF i is maintained. An additionai button®\° allows the voltage to
pin 8 of the EURO-AV socket to be switched off so that a television
receiver on AV operation can be switched to receive normal
terrestrial signals. This is also required by only a few competitor
receivers. GRUNDIG receivers are switched to the AV mode by the
Telepilot. If the customer owns a GRUNDIG TV receiver with the
Telepilot 650 or 660, the Satellite Receiver can be remote-controlled
by operating the "SAT" or "PERI" button and the numbered buttons.
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