Satellite Level Meter
DILAN 2150
Documents (PDF):
Instruction Manual V4.0 (9 pages)
Progamming Example Memory Channel (1 page)
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THE DVB - ANALYSER
MEASUREMENT OF DIGITAL AND ANALOG SATELLITE SIGNALS
Digital video broadcasting via satellite (DVB-S) has become the major force in new television technologies within a very short period of time. What is changing in comparison to the analog technology and which kind of measurement technique is necessary ?
THE DIGITAL CHALLENGE
With the introduction of digital video broadcasting any critiscians expectected heavy problems. But due to solid fundamental research and development this did not appear. Already in 1995 an obligatory DVB-S standard was introduced. For a limited period analog and digital transmissions will coexist. But at the latest to the year 2010 the end of analog transmissions is planned.This does not mean that all analog channels via satellite will disappear. Analog satellite television will remain popular for some time to come.
THE SMALL DIFFERENCE
Whilst the analog system is based on a direct relationship between the carrier-to-noise (C/N) and the quality of the resulting picture, the digital system gives a onsistently good picture quality as soos as a certain C/N level is surpassed.
For this reason it is possible for the first time to make a purely quantitative analysis of the resulting picture quality based on the Bit Error Rate ( BER ), without the need to look at the quality of the actual picture and sound.
This leads us directly to the topic measurement technique.
Like every other real-life transmission system, the digital system can also be impared by interference or errors. These errors may be present at the transmitting side, so that it makes no sense for the installer to identify these errors which cannot be influenced anyway.
It is more important to focus on the receiving side. A minimum C/N value has to be maintained over the complete transmission path at all times. It is also important to evaluate the margin by which the minimum C/N is exceeded in order to compensate the influence of bad weather or gain variations.
It was already mentioned - Starting from a certain minimum C/N a picture transmission without visible disturbances is possible.
PICTURE WELL - ANYTHING WELL ?
Thanks to internal error correction mechanisms even a poor C/N can bring a usable picture. The chart below at a Forward Error Correction (FEC) rate of 3/4 shows the relationship between C/N and picture quality:
<4dB - BER>10-2 - useless - no picture obtainable
4dB - BER~10-2 - insufficient - constant interruptions
5dB - BER<10-2 - unsatisfactory - occasional interruptions
6 dB - BER<10-3 - critical - troublefree operation
7dB - BER<10-4 - sufficient - troublefree operation
8dB- BER<10-5 - fair - troublefree operation
9dB -BER~10-7 - good - troublefree operation
>9dB - BER<10-7 - excellent - troublefree operation
The margin of tolerance between an error-free picture and total failure (black screen) at all is very small. In such a scenario the variation until the picture is lost is little more than 1-2dB.
In order to achieve absolute security it is necassary to use excellent measurement equipment.
Our DILAN 2150 DVB-S Link Analyzer is designed to successively eveluate all the relevant critical parameters for a digital receiver in order to obtain an error-free picture from the available input signal.
On a step-by step basis it checks whether a signal worthy of reception is available at all and what the resulting quality is.
Therefore the following measurement program sequence is started:
Reliable Input Level
Carrier and Synchronisation Regeneration
Carrier-to-Noise Ratio ( C/N )
Bit Error Rate ( BER )
But what sense makes the best availablemeasurement equipment if it is difficult to handle ? Our intention was to design an easy-to-understand and easy-to-operate instrument. After all, who wants to spend hours reading the instructions before operating the device ?
Instead of this a user-friendly concept was developed. Only four buttons are all the meter needs:
Call Menu: MENU key
Changing Parameters: Two soft keys
Acknowledgement: ENTER key
Thanks to the integrated self-intelligence all options of the menu are self-explanatory.
TECHNICAL DATA
Input Frequency Range: (900) 950 - 2150MHz
Input Connector: IEC-standard (F)
Display Range: 30 - 100dBuV
Measurement Range(+/-2dB tolerance): 35 - 95 dBuV
Additional Audio Tone: Variable audio frequency
LNB Voltage (short circuit proof): 0/13/17V max. 250mA
LNB Switching Signals: 22KHz/DiSEqC Vs.1.0
(Hardware for Vs.2.0 already integrated)
Memory Store: 16 individually pre-setted channels
Supply: 15V DC / ca. 380mA without LNC
Dimensions/Weight: 153 x 168 x 60 mm / 0.5kg excl. lead acid battery
DIGITAL SECTION / MPEG-2 Transport Stream Analysis
Symbol Rates: (0.900) 2.000 - 45.000 MS/s
Auto-FEC-Viterbi-Decoder Rates: 1/2;2/3;3/4;5/6;7/8
DVB Synchronisation Display:
SL0: No DVB activity
SL1: Carrier regeneration
SL2: Viterbi decoder synchronized
SL3: De-Interleaver synchronized
SL4 = Front-End-Lock (FEL): FEL-LED illuminated
C/N Measuring Range with FEL: 4 - 20dB
Bit Error Rate (BER) Measuring Range: 10-2 - <10-7
Optional A/V-Card for Analog Satellite TV Signals
With additional analog tuner section; plug-in module is automatically detected.
Video Level: 1Vss / 75W FBAS clamped
Audio Level: 0.6Vss / 1 KW
Video Polarity: Switchable normal/inverse
IF bandwidth: Switchable 18 / 27 MHz
Audio Sub-Carrier Range: 5.00 - 10.00 MHz
Audio Tuning Step-Width: 10 KHz
Audio IF Bandwidth: 150 KHz
RS-232 Interface
Hardware is already integrated (9-pin SUB-D connector); software for remote control is planned.
Accessories
Lead-Acid Battery 12 V / 1.2Ah
Switching Power Supply 100-240V AC / 15V DC 0.8A max. (simultaneously charging & operation)
Alternative: Plug Power Supply 15.2V ~ / 0.6A max. (only for charging)