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Cable Decoder page

 

 

 

 

 

 

      



DISCLAIMER:
Any information found on this page is to be used for education only! Please do not use this info for commercial use.

I do not sell decoders or provide information where to buy decoders! So please do not ask! I do not answere e-mails concerning selling decoders or layout.

On this page you will find all I found about descrambling "MovieHouse and XXX-House". The schematics are published.
The decoder will have an RF input and video output. The level correction will be on video level and not on RF level.
If you want an e-mail when this page is updated, please let me know.


23-03-2002. It's over. UPC Erope has removed all analog encrypted channels from the cable. Now they hope to survive with the digital service.
On the UPC page. You can read the history and news about the set-top box (Dutch only sorry). I'm afraid that UPC will move populair channels behind the set-top box to force more people to rent the box. The target of UPC is to tripple the present costs for their customer, like in the USA.

20-02-2002. Mail me if you want info about the Moviehouse, XXHouse program guide.

22-01-2002. I have added a forum to this page.

19-05-2001. I have adapted the disclaimer. I do not answere e-mail questions about selling decoders or layout anymore, sorry.

10-12-2000. Here you can see some webcam shots. They show the build of a decoder..

13-04-2000. It has been very quite on the cable decoder page. The Movie House decoder is still working.

01-03-2000 (22:00). I have updated the synchronization circuit. I have changed the signal name "VideoIn" to CVBS. I had to do this because of the Scart input option.
The Video level correction circuit is also updated. Q2 is changed to a PNP transistor. This way the top sync will not clip to the ground.
I have added the Scart input circuit. For me the circuit does not work so well because my TV Tuner AGC deforms my CVBS signal see Figuur 13.
01-03-2000 (00:00). I have updated the synchronization circuit. I have added the Blanking signal again.
The Video level correction circuit is also updated, back to what it was. Sorry for the mistake, now only the 4066 is needed.
I have also experimented with the possition of the clamping pulse, but the possition is correct as it is.
I have changed the software. The frequency tabel and the number of frequencies can now be found in the EEProm area. The 2 frequency bytes and the control byte 2 are stored in the EEProm area. The Control byte 2 must sometimes be adapted, for bandswitching see data sheet. So for each channel, 3 bytes are used.
Another change in the software, is the extra delay after POR before initialising the frontend. There was a IC problem.
On address 3Fh the actual Offset is stored of the next channel to come after POR. On address 3E the maximum number of used address must be entered. So when you store 5 channels you need 5*3=15=0Fh memory addresses. On EEProm address 0Eh you will find 0Eh.
I did not have time yet for the scart input design, sorry. I will work on that this week!

07-02-2000 I have checked and changed all schematics. All component references are updated, so they should be unique when you add all schematics together. Please check all schematics. For some of you who have made a layout, the changes are small!
I have changed some values to improve the quality. R14 is changed to 1k5 for less power consumption. C12 and C13 are increased to improve the clamping.
I have added a scart CVBS and AUDIO output. The CVBS output has a amplifier of two. This is due to the load of 75ohm in the TV. Because the clamping circuit is working on 5V, I had to perform a DC shift with Q4 and D5. Q5 and Q6 amplify the CVBS by two. The scart output is sourced by a 68ohm resitor (R22) to get nearly the correct characteristic cable impedance.
I also provide a status signal for the TV scart input. When the decoder 12V power is on, the pin 8 of the scart is activated. This will switch the TV to the scart input where you have connected the decoder.
I could improve the software to control the scart status. So When the signal is encoded activate the status and when not deactivate. But this is for the future.
When only using a 12V power supply, it is possible to use a 5V voltage regulator as given in the power schematic.

22-01-2000 I have updated the Plus channel list for UPC. Avante is a new channel. Thanks Erik.

11-01-2000 I have updated the Video level correction circuit. The power connection to U3 is removed. The PIC schematic is also updated. The vertical blanking output of the PIC is removed.
Some people asked me the software for the 16F84. I explain how this can be done here.

19-12-1999 I have added a pdf file of FQ916 data sheet.
I will not make a layout for this decoder. But if there is someone who is willing to make a layout of the complete decoder, please let me know.

16-12-1999 In many Dutch city's a UPC channel presents a complete tv-guide on teletext page 300.
There are PLUS channels added on the UPC cable network. Thanks Erik. The new channels are added to the channel table. the channels are: Club : Enlish spoken.
Sport 1 : Duth spoken.
Reality TV : English spoken.
Explorer : Dutch spoken.
Film 1 : Dutch subtitle.
At the moment all plus channels are coded like the Movie House channels. So they can be decoded with the decoder on this site.

27-11-1999 I have added more information about controlling the Frontend.
The tuning voltage generator is improved!

22-11-1999 The MCLR function of the processor was NOT correct.

17-11-1999 I have updated the synchronisation circuit. I have deleted the resistor R5 on the input. That resistor should only be used when the Videoin is sourced by a scart output.
I have added the Reset push button. Because it is used for channel select as well.
The value of R8 in the Video level correction circuit is changed to 1k.
The resistor R6 is moved from the Tuning Voltage generator to the frontend schematic. It is important that this resistor is used!
The pin 22 of the frontend was connected to GND. This pin should NOT be connected at all!
Tomorrow I will update the Tuning Voltage generator circuit.

07-11-1999 It has been a while but I will put some time in this page this week.
I have received results from some visitors who have a working decoder, good work!
By the way, I still have some frontends.
This week I will explain how to control the frontend. I will list all registers and their settings. I have a simple DOS program for the frontend but I can not Publish it because of the Copyright sorry.
I will make a dedicated DOS program for the frontend. But first I will explain how it all works so some off you can make your own software. But I understand that UPC tries to get all MovieHouse frequencies the same in the Netherlands, so the internal frequency table in the PIC processor can be used.
I will also publish a very simple IC interface for the parallel port of your computer. I will however work on a NT IC interface that will work on the serial port with Win95 and NT.
So this is what can be found on this page in the near future.
My only problem is ....time. A day has only 24 hours. So please understand that it all will take a while, thanks.

09-10-1999 I have received many questions about the quality of the decoder. Believe me you can get a picture out of it. The decoder set up looks like this.
The decoded line blanking period looks like this.
The Picture.

08-09-1999 I have added the frontend circuit to the schematics. If you want more info about the frontend, please e-mail me. The synchronisation circuit and the video correction schematics are updated.
Also the software is updated. The software now controls the frontend.
Please be patient, I will place more explenation text.


The MovieHouse decoder.

The design is derived from the MaxiPic design.
The decoder syncronisation is based on a 16C84 microprocessor. The processor will lock on the positive edge of the line sync.

FrontEnd

The first part of the design consists of a frontend that receives the MovieHouse Video signal. The first idea was to use the video output of the TV-scart. This has two disadvantageous:
  1. No Recording possible.
  2. AGC distortion possible.
When using a frontend all channels can be received seperate. Due to the stable AGC the video disturbance is low. When the video is disturbed the synchronization is difficult.
The frontend is controlled by the processor. To make the channel switching as easy as possible I have made a table of frequencies in the processor program memory. At every POR of the processor the next frequency from the table will be send to frontend. I will explain the software on a later date.

The Frontend schematic.

The Frontend control

The frontend is internal controlled by the TSA5512. This is a 1.3 GHz IC controlled synthesizer. Here you have the datasheet of the TSA5512.
Here you can download the PDF of FQ916 frontend.

Tuning Voltage generator.

For the varicap tuning diodes in the frontend a voltage of 33V is needed. When you use a lower voltage you are not able to receive the complete frequency range.
The first Voltage genarator did not meet the specification. So I changed it to the present one.
The problem occured at Power On. At that moment there is no VSync present so there is no tuning voltage generated and no tuning possible.

The Tuning voltage generator.

The synchronization processor.

The inverter U1 differentiates the video signal. With R4 the trigger level can be defined. The processor software will open the window by the "Blanking" signal. The principle of the synchronization is very simple. Make a window during a time frame when you expect an positive edge of the synchroniation. Then wait for the positive edge. When the positive edge is detected close the window and wait again for the next positive edge.
The vertical blanking is detected by detecting the absence of the line sync positive edge during the vertical sync. This generates a frame interrupt that restarts a line counter.
I will explain the software in more detail in the near future.
The processor clock frequency is only 8MHz. This causes an synchronization inaccuracy of one machine cycle. If the processor clock frequency would be controlled the accuracy would be better. Maybe if I can find the time I can work on that.

The synchronization circuit.

This is the software for the processor (latest.hex)
Please note that the frequencies that are send to the frontend are fixed in the program. So You have to be patient until I publish the source of the software to edit the frequencies yourself.
The software is intended for the 16C84 processor. If you want to program the software into a 16F84 processor, just set the Power Up Timer Flag after loading the software in the programmer.

The Scart In circuit.

The Scart In circuit.

The Video correction.

The Video correction is based on clamping the video on a different level. The switche U4B clamps the video on the correct Blanking level. This level is the "Ultra" black level of the video. The switch U4A clamps the video on a level that is lower. The switches U4C and U4D will select the correct level. During the active video period the Blanking level is selected and during the blanking period the lower level is selected. This way the synchronization pulses have been shifted down and can be recognized again.

The Video level correction circuit.

Power supply

The simple 12V to 5V regulator.


The theory

The MovieHouse signal has two kind of scrambling methodes. Both have shifted sync, but the sync of the XXX-rated channel is shifted with a different level (in Eindhoven however). I will make some drawings soon, to explain it! When you look at the signal you can see a burst of several period on the front porch of every 4th line sync blanking. The frequency should be 4.88MHz, somebody told me. I will check it. This can be used for synchronization. But it is probably inserted to disturbe the previous Filmnet decoders that uses the negative edge of the line sync to synchronise.
I will use another way for synchronization.
During the past weeks I have received many emails with suggestion. There are many commercial sites, so you will not find any links to them. But thanks to all of you who send me those links!
The most original way of descrambling I received is this one: Use the Promo channel as synchronization source for all MovieHouse channels. They are all synchronised to each other! I have checked it myself. Visit this page regular and you will learn more about it.

I should have started with this but I was to enthusiastic. Here are some drawings that will show how the signals are scarmbled.
I will also show the vertical blanking interval soon.
Figure 1 shows the normal video line blanking interval with the levels and times.
In figure 2 the video is scrambled. In figure 3 the burst is shown. This burst was not present in the old Filmnet video and disturbes every 4th negative line sync edge.
In Fig 4 the blanking period of the XX channel is given. The sync and burst amplitude is reduced by a halve. Only a level shift correction will not be enough! The DC level and amplitude of the sync and burst must be adapted.
I have updated the Line blank diagram. At the moment (14-04-1999) A2000 amsterdam has changed their scramble methode. I myself are not able to do measurements, but M. does. The measurements show in Fig. 6 that the horizontal sync is partly inverted. The video seems to be inverted.
When detecting edgeA I assume the video phase can be detected. At the moment the decoder will probably still lock on the signal, but the vodeo phase will not be correct.


Some camera shots


Picture 1. Line blanking period of Scramble methode A.


Picture 2. Line blanking period of Scramble methode B.


Picture 3. Field blanking period of Scramble methode A.


Picture 4. Field blanking period of Scramble methode B.


Picture 5. Line blanking period of Scramble methode A and E.


Picture 6. Line blanking period of Scramble methode B and E.


Picture 7. Field blanking period of Scramble methode A and E.


Picture 8. Field blanking period of Scramble methode B and E.


Picture 9. This is how the decoder is build.


Picture 10. A decoded line blanking period.


Picture 11. This is how a complete picture looks like.


Picture 12. This is my Desk.


Picture 13. Tuner AGC disturbance on CVBS scart output.


The Decoding table

Some of the scrambled channels have switched to another scramble method. In the table below I have made a summary of all the channels in Eindhoven (Netherlands).
There are 4 different scramble methodes used.
A: 1/3 Horizontal Sync Shift.
B: 2/3 Horizontal Sync Shift.
C: 1/5 Sync amplitude.
D: Negative video.
E: Distorted Horizontal sync Fig. 6 (theory).

When the more than one method is listed, the scramble methode changes random.

I'm sorry to conclude that my present design will synchronise to the distorted horizontal sync (E).
Also synchronising to the color burst will be difficult. Because of the polarity and sync shift change, the IF-AGC will not be stable and so the burst amplitude will change.

Table of Sync shifted Coded Cable Channels in Eindhoven (Netherlands) 22-01-2000

CHANNEL

FREQ. (MHZ)

SCRAMBLE METHODE

LOCK

XX-House

416

A/B/C

1

Movie House 4

408

A

1

Movie House 3

400

A

1

Film 1

712.25

A/B/C/D/E

Explorer

704.25

A/B/C/D/E

Reality TV

696.25

A/B/C/D/E

Sport 1

688.25

A/B/C/D/E

Club 1

680.25

A/B/C/D/E

Avante

743.25

A/B/C/D/E

VH1

376

A/B/C/D/E

Travel Channel/ Adult Channel

368

A/B/C/D/E

Animal Plannet

360

A/B/C/D/E

Muzzik

352

A/B/C/D/E

TNT Clasic Movies

344

A/B/C/D/E

Sky News

335

A/B/C/D/E

ASIANET

328

A

Fashion TV

320

A

Movie House 2

312

A

1

Movie House 1

304

A

1

Movie House Promo

296

-

1


Old design shots

Here you can find old designs that I used in the past for RTL and Filmnet on satellite and cable. I will probably use the drawings again.
The Tuner and IF part will also be easy to build.

VCXO

The first part is the VCXO. The VCXO is build around the CMOS IC 4007. The VCXO generates a 4MHz reference frequency for the sync generator.

Sync Generator

The sync generator is responsible for generating all line related synchronization. For now only the line sync.

Burst gate

The Burst gate will gate the burst out of the CVBS signal. The burstgate signal can be generated by the sync generator. The Burst pulse is active during the burst. The problem with using the burst as synchronization is the phase problem. When the video signal changes in amplitude the phase of the detected burst changes, for the burst envelop is very slow.

Voltage Generator

The Old Tuning voltage generator.



 

 

 

 

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