TeVii cards can partially realize blindscan. Very interesting.

[ter9999]

What almost nobody knows is that TeVii PC-DVB adapters are capable of detecting several transponder parameters blindly. TeVii S464, S470 and S660 are based on the Montage M88DS3000 demodulator which has fully automatic mechanisms to detect modulation, FEC and the presence of pilot symbols for both, DVB-S and DVB-S2. Blindscan of course wouldn抰 be blindscan without symbol rate estimation. And this is why I call the Montage blindscan "partial software". The following limitations apply:

 

 

•for transponders with < 2500 KS/s, blindscan will succeed if the symbol rate set is < ~160% (factor 1.6) off

 

•for transponders with > 2500 KS/s, blindscan will succeed if the symbol rate set is < ~50% (factor 0.5) off

 

 

So the Montage demodulator hardware won抰 blindscan the whole supported symbol rate spectrum of 45 MS/s. You have to take care of this from software. First step is to think about the symbol rates that have to be set from the application to cover the whole 45 MS/s:

 

 

•2500 KS/s (covers range from 0 KS/s ?6500 KS/s with factor 1.6)

 

•12000 KS/s (covers range from 6000 KS/s ?18000 KS/s with factor 0.5)

 

•36000 KS/s (covers range from 18000 KS/s ?45000 KS/s+ with factor 0.5)

 

 

So up to 3 tune requests (or maybe 6, for horizontal and vertical polarization) per frequency, which are executed in few seconds, have to be performed to scan the whole symbol rate spectrum. TransEdit adds the possibility to define the steps (what I call partial software) and afterwards builds all possible combinations:

 

 

 

 

The only problem that is left now is that the TeVii driver won抰 inform the scanning application about the correct transponder parameters, which means that the scanning application can set almost everything and the Montage demodulator will still lock the transponder by blindscanning the correct parameters, but the scanning application thinks that its parameters succeeded and will save those. As a consequence, most other demodulators not supporting blindscan will fail locking. A mechanism is needed for the TeVii driver (API callback function) to report back the correct blindscanned parameters to the scanning application.

 

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Original post at: http://www.dvbshop24.com/index.php?/kunena...with-TeVii.html

[CiNcH]

You can reach this via my blog. See signature...

[ter9999]

For SR < 2500 KS/s, with a factor of 1.6, the spectrum should be 1600 KS/s to 4000 KS/s, so can't cover 4000 to 6500 KS/s?

 

If TeVii driver can realize the callback function as mentioned in the last paragraph, TransEdit may also need to be updated to accept the params.

Edited December 16, 2009 by ter9999

[CiNcH]

For SR < 2500 KS/s, with a factor of 1.6, the spectrum should be 1600 KS/s to 4000 KS/s, so can't cover 4000 to 6500 KS/s?

160% of 2500 = 4000. So blindscan will cover the range 2500 +/- 4000 which is -1500 to 6500 if 2500 is set.

How much the scan covers is dependent on what you set within TransEdit. I just gave an example which should cover the whole 45 MS/s spectrum according to the information given by Montage that blindscan covers +/- 50%/160% of the symbol rate that has been set. You can add more symbol rates to the list so that the spectrum will be scanned redundantly. It is up to you.

 

If TeVii driver can realize the callback function as mentioned in the last paragraph, TransEdit may also need to be updated to accept the params.

That's right yes. But first step is the driver providing an API.

Edited December 16, 2009 by CiNcH

[ter9999]

M88DS3000/2 – Advanced DVB-S/S2 Demodulator

 

The M88DS3000/2 is an advanced single-chip demodulator for digital satellite television broadcasting system. It is fully compliant with the DVB-S/S2 standard and can support QPSK, 8PSK, 16APSK and 32APSK demodulation schemes. The chip provides a fast, easy-to-apply and cost-effective solution for digital satellite receiver front-end design.

 

The M88DS3000/2 accepts baseband differential or single-ended I and Q signals from a tuner, then digitizes, demodulates and decodes the signals, and finally outputs an MPEG transport stream. The M88DS3000/2 supports symbol rates from 1 Msps to 45 Msps, and code rates from 1/4 to 9/10. Its features cover blind scan, fade detection, timing and carrier recovery, performance monitoring, co-channel interference cancellation, command interface, and DiSEqC™ 2.X interface, etc. The device is controlled via a serial 2-wire bus.

 

The M88DS3000/2 works properly with 1.25 V and 3.3 V voltage supplies. Typically, the power consumption is around 350 mW.

 

 

 

Feature

 

• Multi-standard demodulation

- Compliant with DVB-S/S2 specifications

- QPSK, 8PSK, 16APSK and 32APSK demodulation schemes

- Maximum channel bit rate is 130 Mbps

- Maximum symbol rates are: 45 Msps for QPSK and 8PSK; 36 Msps for 16APSK and

28 Msps for 32APSK

 

• DSP features

- Symbol rate sweeping

- I/Q impairment cancellation

- Automatic spectrum inversion

- Adaptive equalizer for RF reflection removal

- Roll-off factor automatic identification

- Fast blind scan - High performance on-chip micro-controller

- Multi-error monitor

- Accurate SNR estimation

- Multi-lock indicators

- Clipping rate reporter

- DC removal

- Automatic frequency correction

- Fast timing loop acquisition

- Robust frame synchronization scheme

- Phase noise indicator

- Fast system recovery from fading or other abnormal conditions

- Co-channel interference cancellation

- Constellation monitor

 

• Interface

- DVB-S/S2 common, parallel and serial MPEG output interfaces compliant

- Serial 2-wire bus to configure the device

- 2-wire bus repeater for tuner configuration

- DiSEqC™ 2.X compliant interface

- General purpose output

- Dedicated reference clocks (13.5MHz / 27MHz) generation

 

• System

- On-chip 8-bit ADC

- On-chip PLL for system clock generation from a 27 MHz external clock or quartz

crystal

- Sleep mode supported

 

• Technology

- Power supplies: 1.25 V and 3.3 V

- Low power consumption: 350 mW

- Green package: LQFP 100-pin exposed pad (M88DS3000); 64-pin QFN (M88DS3002)

 

 

 

Application

 

• Digital satellite set-top boxes

• Digital satellite receivers