20.1TOP SIDE ASSEMBLY DRAWING ............................................................................................. 17
20.2BOTTOM SIDE ASSEMBLY DRAWING ...................................................................................... 17
1 CHANGE HISTORY
2
1. CHANGE HISTORY
Revision Date Author Comments
Rev 1.07/23/2000Jim LoughinInitial Release
Rev 1.18/23/2000Jim LoughinUpdated to match final design
2.GENERAL DESCRIPTION
Major functional blocks are discussed briefly in this section. A more detailed description is contained later in the document.
2.1 STI5508
The STi5508 provides a highly integrated back-end solution for DVD applications. A host CPU handles both the general
application (the user interface, and the DVD, CD-DA, VCD, SVCD navigation) and the drivers of the different embedded
peripheral (audio/video, karaoke, sub-picture decoders, OSD, PAL/NTSC encoder...). Because of its memory savings,
increased number of internal peripherals, improved development platform and reference design, theSTi5508 offers a costeffective solution to DVD applications, with rapid time-to-market. These functions include:
Integrated 32-bit host CPU @ 60MHz
- 2 Kbytes of instruction cache, 2 Kbytes of data cache, and 4Kbytes of SRAM configurable as data cache.
Please refer to the STi5508 Data Sheets: STi5508 DVD HOST PROCESSOR WITH ENHANCEDAUDIO FEATURES and STi5508 REGISTER MANUAL for more detailed information.
2.2 MEMORY
The STi5508 includes all of the interface signals to connect to industry standard SDRAM, DRAM, ROM, and I2C memory
devices. The system includes one or two SDRAM components. The MPEG decoder unit interfaces to a single 4M x 16bit
SDRAM over the SMI bus. The general purpose processor can share the decoder SDRAM or can access an optional
SDRAM installed on the EMI bus. This EMI SDRAM can be either a 1Mx16 or 4Mx16 chip. The optional EMI SDRAM can
be installed if the system requires higher performance of requires more RAM than is standard system (due to complex trick
modes, advanced GUI, etc). The standard production Ravisent CineMasterCE software will execute without EMI SDRAM
installed, however EMI SDRAM is required to perform debugging and prototyping. A single 1Mx16 FLASH ROM device is
support on the EMI bus. There is also a small I²C serial EEPROM (from 1Kbit to 256Kbit) for storage of user player settings,
software configuration information, title specific information, or other purposes.
3
2.3 DRIVE INTERFACES
The system supports either a standard ATAPI drive interface or the SGS Thomson TVM502 drive (simply called TMM).
The TMM drive is supplied with either a three connector interface or a single FFC cable connection. The design supports
either connection method. The TMM three connector interface utilizes separate connectors for power, data, and drive tray
motor control. Circuitry to control the TMM drive tray is located on the decoder board when this TMM drive version is
used. The interface to the ATAPI drive is included within the STi5508. The ATAPI data bus is buffered so that the ATAPI
cable does not interfere with signal quality. An ATAPI drive is connected via the standard 34 pin dual row PC style IDE
header. An IDE power connector is also supported for convenience.
2.4 FRONT PANEL
The front panel is included in the reference design and is based around an inexpensive Futaba VFD and a common NEC
front panel controller chip, (uPD16311). The STi5508 controls the uPD16311 using several control signals, (clock, data,
chip select). The infra-red remote control signal is passed directly to the STi5508 for decoding.
A more advanced front panel is possible with the addition of a front panel microcontroller. A Microchip PIC can be used to
control the 16311, receive the infra-red remote control decoding, and system power down. Communication between the
STi5508 and the front panel PIC is accomplished over an I²C interface.
The front panel connector also supports two microphone inputs and a stereo headphone output.
2.5 REAR PANEL
A typical rear panel is included in the reference design. This rear panel supports:
- Six channel and two channel simultaneous audio outputs
- Optical and coax S/PDIF outputs are supported
- Composite, S-Video, and RBG/YUV outputs
- Dual SCART provides SCART passthrough when DVD output is not supplied
- External video DENC Connections
The six video signals used to provide CVBS, S-Video, and RGB/YUV are generated by the STi5508s internal video DAC.
The video signals are be buffered by external circuitry. The STi5508 can generate either RGB or YUV outputs on three of
the pins by configuring internal STi5508 registers.
Six channel audio output by the STi5508 in the form of three I²S (or similar) data streams. An addition, an I²S stream is
generated by the STi5508 to support simultaneous two-channel output. The S/PDIF serial stream is also generated by
the STi5508 output by the rear panel. A six-channel audio DAC, a stereo DAC, or both can be installed.
3 GPIO, IRQ, AND CHIP SELECT ASSIGNMENTS
PIO Port BitPin #STi5508 Alternate FunctionCineMaster CE Function
Port 0 Bit 0186SC0_DATA#SOFT_RESET
Port 0 Bit 1187#ATAPI_RD#ATAPI_RD
Port 0 Bit 2188#ATAPI_WR#ATAPI_WR
Port 0 Bit 3189SC0_CLKDAC_CCLK (Audio DAC control)
Port 0 Bit 4190SC0_RSTDAC_CCLK (Audio DAC control)
Port 0 Bit 5191SC0_CMD_VCC#DAC_CS0 (Audio DAC control)
Port 0 Bit 6192SC0_DATA_DIR#DAC_CS1 (Audio DAC control)
Port 0 Bit 7193SC0_DETECTUnused (Test Point 39)
Port 1 Bit 0194SSC0_DATASDA (I2C)
Port 1 Bit 1195SSC0_CLKSCL (I2C)
Port 1 Bit 2196PARA_DVALID/SC_EXT_CLKUnused (Test Point 35)
Port 1 Bit 3197TXD2TXD (Serial Port)
Port 1 Bit 4200RXD2RXD (Serial Port)
Port 1 Bit 5201PARA_SYNC/TXD1SR0 (for PLL1700)
Port 1 Bit 6202TRIGINTRIGIN (JTAG)
Port 1 Bit 7203TRIGOUTTRIGOUT (JTAG)
Port 2 Bit 0204SC1_DATAFPCLK (Front Panel)
Port 2 Bit 1205PARA_REQ/RXD1FS0 (for PLL1700)
Port 2 Bit 2206PARA_STRFS1 (for PLL1700)
Port 2 Bit 3207SC1_CLKRTS (Serial Port)
Port 2 Bit 4208SC1_RSTCTS (Serial Port)
Port 2 Bit 51SC1_CMD_VCCFPDATA (Front Panel)
Port 2 Bit 62DAC_DATA/SC1_DATA_DIRDAC_DATA (Stereo Audýo)
Port 2 Bit 73SC1_DETECTFPSTRB (Front Panel)
4
Port 3 Bit 06PARA_DATA0OPEN (TMM Tray Control)
Port 3 Bit 17PARA_DATA1CLOSE (TMM Tray Control)
Port 3 Bit 28PARA_DATA2Unused (Test Point 36)
Port 3 Bit 39PARA_DATA3Front Panel IR
Port 3 Bit 410PARA_DATA4Unused (Test Point 37)
Port 3 Bit 511PARA_DATA5Unused (Test Point 38)
Port 3 Bit 612PARA_DATA6/COMP1#SENSE (TMM Tray Control)
Port 3 Bit 713PARA_DATA7/COMP2#PUSH (TMM Tray Control)
Port 4 Bit 039YUV0YUV0 (External Video DENC)
Port 4 Bit 140YUV1YUV1
Port 4 Bit 241YUV2YUV2
Port 4 Bit 342YUV3YUV3
Port 4 Bit 443YUV4YUV4
Port 4 Bit 544YUV5YUV5
Port 4 Bit 645YUV6YUV6
Port 4 Bit 746YUV7YUV7
* Front Panel uses the 16311 controller. In the CineMaster design, FPDIN and FPDOUT are connected
together as FPDATA.
Pin Name Pin #STi5508 Pin FunctionCineMaster CE Function
Jumper FunctionInstalledNot Installed
JP1 Power +3.3V, +5V and +12V areUninstalled all
Down disconnected from thecomponents are powered
STi5508 and associated
circuitry using a FET switch
JP3 Boot Fromforces STi5508 to boot fromNot Installed STi5508 will
LinkJTAG interface only attempt to boot from
FLASH, but will also boot
from JTAG interface
* Note: There is no JP2
Table 2 Jumper Configuration
5. AUDIO OUTPUT
The STi5508 supports both a six channel analog output and a stereo output configuration. Both of these output configurations are available simultaneously (eight analog outputs total). In a system configuration with six analog outputs, the front
left and right channels can be configured to provide the stereo outputs, Dolby Surround, and SRS TruSurround, or the left
and right front channels for a 5.1 channel surround system.
The STi5508 also provides a stereo output channel that can be used in combination with the 5.1 outputs. An example of
this configuration is a DVD player with these stereo outputs connected to the TV and the six channel outputs connected
to the surround sound amplifier unit. In this setup, the consumer can use the TV speakers or the surround speaker
without changing any wires. The stereo output can be configured separately from the six-channel left and right outputs,
so, for example, the stereo output can be configured for Dolby ProLogic.
The Sti5508 also provides digital output in S/PDIF format. The evaluation board supports both optical and coaxial
S/PDIF outputs.
5.1 AUDIO DACs
The STi5508 supports several variations of an I²S type bus, varying the order of the data bits (leading or no leading zero
bit, left or right alignment within frame, and MSB or LSB first) is possible using the Sti5508 internal configuration registers.
The I²S format uses four stereo data lines and three clock lines. The I²S data and clock lines can be connected directly to
one or more audio DAC to generate analog audio output.
5
The evaluation board uses a six-channel DAC and also a two-channel DAC. The six-channel DAC is connected to the
three STI5508 data signals for six-channel output and the two-channel DAC is connected to the STi5508 optional stereo
output. The board can be configured with either the six- or two-channel DAC, or both. When the two-channel DAC is not
used, the left and right front audio can be connected to the stereo audio output connectors by installing zero ohm resistors R364 and R365.
The six-channel DAC is an AKM AK4356. The two-channel DAC is an AK4394 also made by AKM. Both of these DACs
support up to 192Khz sampling rate. A less expensive 96kHz two-channel DAC with the same pin-out can be placed
instead of the AK4394. Four STi5508 PIO pins are used to configure the audio DACs. The outputs of the DACs are
differential, not single ended so a slightly more expensive buffering circuit is required. The buffer circuits use NJR
NJM5532 opamps to perform the low-pass filtering and the buffering.
5.2 AUDIO MUTE
The audio DACs contain an internal mute circuit and can be enabled by the STi5508 PIO pins. The evaluation board may
output a small pop when the system is powered on and off, but no audible pops should be heard during operation or
when entering or leaving standby mode.
6. VIDEO INTERFACE
The STi5508 integrates a PAL/NTSC encoder. It converts the digital MPEG/Sub Picture/OSD stream into a standard
analog baseband PAL/NTSC signals. Six analog video outputs provide CVBS, S-Video (Y/C), and RGB/YUV formats. The
three RGB signals can be configured via an internal STi5508 register setting to output either RGB or YUV video signals.
The encoder handles interlaced and non-interlaced mode. It can perform Closed Captions, CGMS or Teletext encoding
and allows Macrovision 7.01/6.1 copy protection. The encoder supports both master and slave modes for synchronization.
The six video signals are routed to the back panel where they are low-pass filtered and buffered. The six active video
buffer circuits on the decoder board are identical and use a video speed MAX4018 opamp made by Maxim.
The buffered CVBS video is available on a RCA (cinch) style jack, S-Video on a mini-DIN, RGB/YUV on a triple RCA
jack, and all six signals (and stereo audio) are available on a SCART connector.
Note:The STi5508 is not capable of placing the video synch information in the green signal as required by some RGB
monitors. The synch information must be obtained from the CVBS output and connected to the external sync input of an
RGB monitor.
Note:When the STi5508 is configured to output YUV signals, the RGB pins of the SCART connector will also output YUV.
6.1 SCART INTERFACE
The Ravisent evaluation board contains a SCART controller chip from ST Microelectronics, the STv6412. This controller
chip allows SCART daisy-chaining the SCART output from another device can be connected to the DVD player SCART
input and passed through when the DVD player is in standby.
All SCART functions are controlled by the 6412 chip, which is in turn controlled by the STi5508 over the I²C bus. Please
see the STv6412 AUDIO/VIDEO SWITCH MATRIX data sheet for more detailed information.
6.2 DIGITAL VIDEO INTERFACE
An external video DENC can be connected to the STi5508. The digital output and analog input headers are provided on the
board, J20 and J19 respectively. The video encoder is controlled via I2C through the header. Also supplied on the header
are +3.3V, +5V, ground, and +5V and 5V analog supplies. The output of the external DENC is then fed into the video
filter-buffers on board. The values of the discrete components in the filter-buffers should be changed to match the characteristics of the external DENC.
7. MPEG DECODER SDRAM MEMORY
The STi5508 includes glueless interfaces to SDRAM memory for the MPEG decoder. The STi5508 supports one or two
1Mx16bit chips or a 4Mx16bit SDRAM chip. However, the Ravisent evaluation board supports only a 64Mbit chip. The
device used is a 4M x 16 bit, 125MHz, 3.3V, 54 pin TSOP II, Micron Technology MCT48LC4M16A2TG-7 or equivalent.
8. PROCESSOR SDRAM MEMORY
The STi5508 supports DRAM or SDRAM on its processor bus without any glue logic required. The Ravisent evaluation
board supports only SDRAM - either a 1Mx16bit or a 4Mx16bit SDRAM. The STi5508 processor can be configured to
share the decoder memory. This will reduce performance slightly, but will reduce the cost of the system, as processor
SDRAM is no longer required. It is expected that a typical DVD player will not need any processor SDRAM and this chips
will only be installed for test and debug purposes.
Dual PCB footprints were used to accommodate the differences in packaging between 16M and 64M SDRAMS. U5/1 is
the 16Mbit footprint and U5/2 is the 64Mbit footprint. The same 64Mbit SDRAM used for decoder memory can be used for
processor SDRAM.
6
9. FLASH MEMORY
The decoder board supports a single 1Mx16bit FLASH memory device. The device is a 1M x 16, 90ns, bottom boot block,
3.3V, 48 pin TSOP II, SGS Thomson M29F160BB-90N1 or equivalent. Both 3.3V and 5V FLASH devices can be installed.
Our current FLASH loading software supports several FLASH chips from different manufacturers. To support new chips, the
programming algorithm will have to be adapted, but this is a rather simple adaptation.
Note: Intel and Micron FLASH require that pins 13 and 14 are tied to the positive power supply to allow programming in
circuit. To support these device families, install zero ohm (0R0) resistors in locations R79 and R80.
Note: Install a zero ohm resistor in location R350 to support +5V FLASH. Install zero ohms in R352 to support +3.3V
FLASH. Never install both R350 and R352 at the same time as this will short the 3.3 and 5V supplies together. The default
is +3.3V.
Note: Some FLASH devices use pin 15 for address pin A19, while most others use pin 9. To support a chip that uses pin
15, install R81.
10. SERIAL EEPROM MEMORY
An I²C serial EEPROM is used to store user configuration (i.e. language preferences, speaker setup, etc.) and software
configuration information (i.e. remote control type). Industry standard EEPROM range in size from 1kbit to 256kbit and
share the same IC footprint and pinout. The default device is 2kbit, 256k x 8, SOIC8 SGS Thomson ST24C02M1 or
equivalent. See the section on Reset Circuitry for a less costly EEPROM solution.
11. TMM DRIVE INTERFACE
The STi5508 will directly supports a Thomson TVM502 drive (or a similar drive built around the ST chip drive set) without
any external glue logic. The newer TVM drives include the disc tray motor control circuitry, but the older drives do not.
Tray motor control circuitry is included on the evaluation board to support these older drives.
11.1 CONNECTION INFORMATION
The newer TMM drive uses a 19 pin FFC connector while the older drives use two PicoFlex ribbon connectors and a
two pin tray motor connector. Both connector systems are supported on the evaluation board. The drive interface, with
the exception of the tray motor circuitry, is contained entirely in the STi5508.
The older TMM drive connects to the evaluation board in three places:
J5 Drive tray motor terminals
J6 Power cable connector
J7 Data cable connector
The newer TMM drive connects to the evaluation board with a single connector:
J8 FFC19 connector
The connectors selected by Thomson for the data and power cables are in the PicoFlex product line manufactured by Molex
and Lumberg. The FFC connector is available from many suppliers including Molex. See Bill of Material for part numbers.
11.2 TMM DRIVE TRAY MOTOR CONTROL AND PUSH AND STALL SENSE CIRCUITRY
There is circuitry on the decoder board to power the TMM drive tray and to monitor its activity. When the tray is being
opened or closed and the tray has reached the end of its travel or is being jammed, the motor will stall and draw a high
current. Circuitry monitors the level of current used by the motor and will toggle a PIO pin of the STi5508 when the motor
has stalled, (schematic net name: #SENSE). The STi5508 will then remove power to the motor. Also, if the tray is open and
the user pushes the tray to close it, the motor will generate voltage. Circuitry will sense this voltage and toggle another PIO
pin, (schematic net name: #PUSH). The STi5508 will then close the tray.
The sensitivity of the push sense can be adjusted by changing the value of R114 in relation to R117. When the tray is
motionless, the voltage across the motor is zero. When the tray is pushed the voltages at either side of the motor begin to
diverge. These two voltages are fed into a comparator to create the trigger signal. This is an improved circuit from the
Ravisent STi5505 evaluation boards and this new circuit is not sensitive to temperature or component tolerances.
Note: To disable the push sense circuit, remove R109 and R112. R106 and R107 should already be installed.
12. ATAPI DRIVE INTERFACE AND EPLD
The STi5508 includes a glueless ATAPI interface on-chip. While this interface limits performance of the system, it is a lower
cost solution than providing external logic to interface the drive to the STi5508 front-end interface.
Standard ATAPI DVD drives are supported through the ATAPI EPLD interface. The drive connects to the decoder board
through a standard 40 pin header, The header is a 2 row by x 20 pins, 0.1 pin spacing, and has 0.025 square pins.
Note: The decoder board supports the standard ATAPI electrical connections, but the software protocol within the drive is
not always supported according to ATAPI specifications. Custom software may need to be developed and tested to support
ATAPI drives from different manufacturers.
7
13 AUDIO SAMPLING RATE AND EXTERNAL PLL COMPONENT CONFIGURATION
The decoder board has optional PLLs, which can be installed to provide the audio clock for the system. The initial version
of the STi5505 was not able to provide an audio clock for 96kHz support and an external PLL was used to support this.
This was fixed in the STi5505 later chip revisions and therefore no problems are expected in the STi5508. However, in
case a problem arises, the PLL circuit can be installed to provide a high quality clock particularly important in S/PDIF
applications. In the default configuration, a small buffer chip is installed to buffer the audio clock between the STi5508
and the audio DACs.
14 UART SERIAL PORT
The evaluation board provides an RS232 connection to the STi5508. A standard DB9 connector ribbon cable can be
connected to the 10 pin header provided, (J9). The RS232 buffer can also be bypassed and the 3.3V signals can be
accessed on the header. ASC2 is the serial port used to this connection.
15. FRONT PANEL
15.1 FRONT PANEL MICRO
A Microchip PIC can be installed in the system to control the front panel VFD, perform IR remote control decoding and
power down functions, and read the position on two POTs with its internal ADC. When the front panel micro is installed,
the entire decoder board circuit can be powered down in standby mode because the PIC will decode the IR signals.
15.2 VFD CONTROLLER
The VFD controller is a NEC uPD16311. This controller is not a processor, but does include a simple state machine
which scans the VFD and reads the front panel button matrix. The 16311 also includes RAM so it can store the current
state of all the VFD icons and segments. Therefore, the 16311 need only be accessed when the VFD status changes
and when the button status is read. The STI5508 can control this chip directly using PIO pins or can allow the front panel
PIC to control the VFD.
15.3 MICROPHONE INPUTS
The board has two ¼ phono-jacks for microphone input. The microphone circuits consist of microphone pre-amps, a
signal buffers, and a stereo ADC. The microphone pre-amp, SSM2165, conditions the signal for better performance. The
stereo ADC is a Crystal CS5331 and connects directly to the STi5508 digital audio input via I²S.
Adjusting the value POT1 and POT2 can vary the compression characteristics of the microphone signal. See the
SSM2165 data sheet for a graph of the compression characteristics and POT settings. When the correct POT setting is
found, the pots can be replaced with fixed resistors, R382 and R383.
15.4 HEADPHONE OUTPUTS
The left and right audio is amplified and output through a stereo ¼ phono-jack. The audio is from the two-channel output,
not the let and right channel of the six-channel, (the left and right six-channel audio can be connected to the left and right
two-channel output when the stereo DAC is not installed). A dual logarithmic POT is used to adjust the volume of the
audio before amplification, POT5. The connections for left and right channels at the headphone jack can be swapped by
changing the resistor stuffing options, R376-379
.
16 MISCELLANEOUS FUNCTIONS
16.1 POWER DOWN
Two dual FET ICs can be installed on the decoder board to enable a power down feature. Power down is activated by
connecting a switch across JP1, shorting the two pins together pulling pin 2 to +5V. The front panel microcontroller can
also control the power down status by driving FPPWD high. When in power down state, power can be removed from all of
the circuitry except the front panel micro, which must remain power to decode remote control signaling and scanning the
front panel buttons. If the front panel micro is not used, then the STi5508 cannot be powered down.
The board can be configured in several ways to accomplish a power down goal. The net VCC_PIC is always powered.
VCC can either be switched (by installing R3) or always powered (by installing R1). VCC3 can either be switched (by
installing R5)or always powered (by installing R2). VCC-S, VCC3-S, +12V-S, and +8V-S are switched. There are four
LEDs used to indicate power state and they can be connected on either side of the FET switch. The dual FET is a
Fairchild NDS8934 and is located at Q1 and Q2.
Note: If the power down feature is enabled FPPWD must be driven by the front panel micro or some other source.
16.2 RESET CIRCUITRY
Three different chips are supported to provide the power-on-reset and pushbutton reset function: Analog Device ADM707
(or equivalent), Telcom Semiconductor TC1270, or Xicor X1242. The TC1270 is a lower cost alternative to the ADM707.
The Xicor device also includes 2kbits of Serial EEPROM storage and can be used to replace both the reset and
SEEPROM devices to reduce cost. All three devices support and pushbutton reset switch.
8
16.3 VOLTAGE REGULATORS
There are two +5V linear regulators to generate +5V for the analog circuitry from +12V. A smaller DPAK surface mount
device can be used in most circumstances, but in applications were more than 150mA are required, a TO-220 throughhole package can be used.
The STi5508 requires 2.5V to operate. This voltage is generated from +5V.
Negative 5V is required by the audio buffer circuitry and this is generated in one of three ways. If 12V is supplied by the
power supply, it is regulated to 5V with a linear regulator. If no 12V is supplied, a DC-DC can be installed in U51 to
generate either 12V or 5V. The use of a switching regulator to generate the negative voltage may introduce noise into
that voltage, so better audio performance may be produced by generating 12V with the DC-DC converter and then
regulating this to 5V with a linear regulator.
2. SMALL SIGNAL PART WITH STV2248.................................................................................... 3
• 2.1 Vision IF amplifier...................................................................................................................................................................3
• 2.3 AM demodulator ...................................................................................................................................................................3
• 2.4 FM demodulator ....................................................................................................................................................................3
• 2.5 Video switch............................................................................................................................................................................4
6. VERTICAL OUTPUT STAGE WITH TDA8174A....................................................................................................................7
7. VIDEO OUTPUT AMPLIFIER STV5114...................................................................................................................................7
8. POWER SUPPLY (SMPS) ............................................................................................................................................................7
10. SERIAL ACCESS CMOS 8K EEPROM 24C08.....................................................................................................................7
GENERAL BLOCK DIAGRAM of 11AK46.................................................................................................................................17
Service menu ....................................................................................................................................................................................18
DO NOT CHANGE ANY MODULE UNLESS THE SET IS SWITCHED OFF
The mains supply part of the switch mode power supply’s transformer is live.
Use an isolating transformer.
The receiver complies with the safety requirements.
SAFETY PRECAUTIONS:
The service of this TV set must be carried out by qualified persons only. Components marked
with the warning symbol on the circuit diagram are critical for safety and must only be replaced with an
identical component.
- Power resistor and fused resistors must be mounted in an identical manner to the original component.
- When servicing this TV, check that the EHT does not exceed 26kV.
TV set switched off:
Make short-circuit between HV-CRT clip and CRT ground layer.
Short C809 before changing IC800 or other components in primary side of the SMPS part.
Measurements:
Voltage readings and oscilloscope traces are measured under the following conditions:
Antenna signal’s level is 60dB at the color bar pattern from the TV pattern generator. (100% white, 75%
color saturation)
Brightness, contrast, and color are adjusted for normal picture performance.
Mains supply, 220VAC, 50Hz.
PERI-TV SOCKET
- The figure of PERI-TV socket-
SCART 1 PINING
1 Audio right output0.5Vrms / 1K
2 Audio right input0.5Vrms / 10K
3 Audio left output0.5Vrms / 1K
4 Ground AF
5 Ground Blue
6 Audio left input0.5Vrms / 10K
7 Blue input0.7Vpp / 75ohm
8 AV switching input0-12VDC /10K
9 Ground Green
10 11 Green input0.7Vpp / 75ohm
12 13 Ground Red
14 Ground Blanking
15 Red input0.7Vpp / 75ohm
16 Blanking input0-0.4VDC, 1-3VDC / 75 Ohm
17 Ground CVBS output
18 Ground CVBS input
11AK46 is a 90° chassis capable of driving 14” tubes at the appropriate currents. The chassis is capable
of operating in PAL, SECAM and NTSC standards. The sound system is capable of giving 3,5 watt
RMS output into a load of 8 ohms. One page, 7 page SIMPLETEXT, TOPTEXT, FASTTEXT and US
Closed Caption is also provided. The chassis is equipped with a 42 pin Scart connector.
2. SMALL SIGNAL PART WITH STV2248:
STV2248 video processor is essential for realizing all small signal functions for a color TV receiver.
2.1 Vision IF amplifier3
The vision IF amplifier can demodulate signals with positive and negative modulation. The PLL
demodulator is completely alignment-free. Although the VCO (Toko-coil) of the PLL circuit is external,
yet the frequency is fixed to the required value by the original manufacturer thus the Toko-coil does not
need to be adjusted manually. The setting of the various frequencies (38.9 or 45.75 MHz) can be made
via changing the coil itself.
2.2 QSS Sound circuit (QSS versions)
The sound IF amplifier is similar to the vision IF amplifier and has an external AGC de-coupling capacitor.
The single reference QSS mixer is realised by a multiplier. In this multiplier the SIF signal is converted to
the inter-carrier frequency by mixing it with the regenerated picture carrier from the VCO. The mixer
output signal is supplied to the output via a high-pass filter for attenuation of the residual video signals.
With this system a high performance hi-fi stereo sound processing can be achieved. The AM sound
demodulator is realised by a multiplier. The modulated sound IF signal is multiplied in phase with the
limited SIF signal. The demodulator output signal is supplied to the output via a low-pass filter for
attenuation of the carrier harmonics. The AM signal is supplied to the output via the volume control.
2.3 AM DEMODULATOR
The AM demodulated signal results from multiplying the input signal by itself, it is available on
AM/FM output.
2.4 FM demodulator and audio amplifier :
The FM demodulator is realized as narrow-band PLL with external loop filter, which provides the
necessary selectivity without using an external band-pass filter. To obtain a good selectivity a linear phase
detector and constant input signal amplitude are required. For this reason the inter-carrier signal is
internally supplied to the demodulator via a gain controlled amplifier and AGC circuit. The nominal
frequency of the demodulator is tuned to the required frequency (4.5/5.5/6.0/6.5 MHz) by means of a
calibration circuit that uses the clock frequency of the µ-controller/Teletext decoder as a reference. The
setting to the wanted frequency is realized by means of the software. It can be read whether the PLL
frequency is inside or outside the window and whether the PLL is in lock or not. With this information it is
possible to make an automatic search system for the incoming sound frequency. This is realized by means
“13
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