* A RASTR-15 system is intended for arrangement of digital TV broadcasting and data transmission to remote locations with
transformation into the initial digital group packet data at a transmitted signal receiving side.
* Digital TV broadcasting is effected in the DVB-C and the DBV-S standards
* Technical description and manual for RASTR-15 (557 kb)
TA-15/36SL transmitting antenna, TDS-6.5/10 digital group transmitter and receiving RASTR converter with antenna
The RASTR-15 system consists of three parts: transmitting part, receiving part, shaping part.
RASTR-15 shaping part composition depends on the digital TV broadcasting standard: DVB-C (QAM) or DVB-S (QPSK). The equipment composition and the technical specifications for a QAM modulation are considered as an example.
Shaping part of the system may consist of:
- "CON-100 A/D" Digital Transducers shaping an ASI stream (EN300421 standard) from 8 analog video signals with stereo accompanying sound;
- "MCD-110/4-19" QAM Modulator Modules effecting signal modulation in the DVB-C standard. One modulator shapes one digital TV packet from four transport bitstreams. There is an internal summator in every modulator. Use of two or more modulators enables group signal shaping by summing digital TV packets;
- "Converter" Group Frequency Converter, converting group signal of the DVB-C standard, channel centre frequencies in the range of 234...481MHz into the range of 954...1201MHz; conversion ratio +8 ±2dB, group signal maximum input level -8dB/mW.
Quantity of "CON-100 A/D" digital transducers and "MCD-110/4-19" QAM modulators depends on the quantity of shaped packets.
A Transmitting Part consists of:
- "TDS-6.5/10" Group Digital Transmittertransforming satellite IF signal into microwave signal with its amplification
- "PS-138/10-30" Power Supply Source;
- "ÒÀ-15/360SL" Transmitting Antennaoperating in the frequency band of 6...6,6GHz with a vertical polarization and a circular antenna diagram, a 6 dB amplification, with a 1,7 VSWR.
A Receiving Part consists of:
- RASTR Receiving Converteramplifying the received signal into its TV range
- Receiving Antenna (a standard satellite antenna of a 0,9 m diameter);
- Power Supply Source PS-105F/121-1,5 ;
- CRD-200Ì Subscriber Cable Receiver.
|RASTR System Common Technical Specifications|
|Operating Frequency Range||6,170 ... 6.425 GHz|
|Modulation Kinds||QAM16, QAM64, QPSK|
| Coverage Area Radius
- when QAM16
- when QAM64
- when QPSK
up to 16 km
up to 8 km
up to 24 km
|Broadcast Channel Maximum Quantity||48|
|Emitted Radio Signal Polarization||Vertical|
ÒTDS-6,5/10 Digital Group Transmitter
|Operating Frequency Range||6.170...6.425 GHz|
|Input Frequency Range||950...2150 MHz|
|AGC Dynamic Range||20 dB|
|Input Signal Maximum Total Power||-5 dB/mW|
|(Total) Maximum Output Power, when Intermodulation Distortions of the 3d Degree -40dB||3 W|
|Converter Gain not lower than||50 dB|
|RF Transmission Line Amplitude Frequency Characteristic Unevenness||± 1.5 dB|
|Out-of-Band Distortion Levels||> 50 dB|
|Heterodyne Frequency||7375 MHz|
|Heterodyne Frequency in the Operating Frequency Range of -40 îÑ to +50 îÑ||2 ppm|
|Phase noise level while tuning-out by ± 10kHz||-70 dBc|
|Phase Noise Level while tuning-out by ± 100kHz||-95 dBc|
|Heterodyne Oscillator Signal Suppression relatively to output signal not less than||> 55 dB|
|Voltage Supply/Consumption Current||10 V / 25 A|
|Baking Time not less||10 min|
|Operation Temperature||-40 îÑ up to +50 îÑ|
|Dimensions (without mounts)||360x320x110 mm|
Subscriber Receiving Converter
|Input Frequency Range||6.170...6.425 GHz|
|Frequency Output Range||607...862 MHz|
|Heterodyne Frequency||5563 MHz|
|Heterodyne Frequency Instability||2 ppm|
|Phase Noise Level while tuning-out by ± 10kHz||-65 dBc|
|Phase Noise Level while tuning-out by ± 100kHz||-90 dBc|
|Noise Ratio including Selection Filter||3 dB|
|Suppression over Image Channel||> 40 dB|
|Voltage Supply/Consumption Current*||9...12V /0,15 A|
|Operation Temperature||-40 îÑ up to +50 îÑ|
Let us consider RASTR-15 system operation according to a structure scheme in fig. 1.
Each of the six "ÑON-100A/D" digital transducers shape an ASI digital bitstream (EN300421 standard) from eight video signals with stereo accompanying sound at the transmitting part of the RASTR system shaping part. The shaped digital bitstreams arrive to the "MCD-110/4-19" modulator outputs afterwards. Signal modulation in the DVB-C standard occurs there. One modulator shapes one digital TV packet from four transport streams. There is an internal summator in each modulator. Use of two or more modulators enables group signal shaping by summing digital TV packets. The group signal in the "Converter" converter is transformed in the satellite range IF and is injected into a transmitting part to a "TDS-6.5/10" group transmitter over a drop cable. A DP-1/69 variable attenuator is installed between the group transmitter and the satellite IF converter for an additional adjustment of the injected signal.
The "TDS-6.5/10" transmitter is installed on the mast, the satellite IF group signal is injected into the transmitter input over a drop cable, the signal is transformed into microwave signal and is amplified. The "TDS-6.5/10" AGC system maintains the total output power level. "TDS-6.5/10" power supply is effected by a PS-138/10-30 power supply source .
Group signal is injected form output digital transmitter to a TA-15/360SL antenna with a circular polarization and is emitted over-the-air. The receiving antenna receives the signal arriving to the RASTR-15 receiving converter input for a further amplification and signal transformation into a TV range. The signal arrives from the receiver output to the CRD-200Ì receiver input where it is demodulated. The signal from the CRD-200M output can be used to view on a TV set.
RASTR-15 receiving converter dynamic range and receiving antenna antenna diagram peculiarity enables signal receiving at a 150m distance from a transmitting antenna successfully without receiving part overloading. Reception is conducted while having a 30 dB SNR with the error ratio of 2-3*10-6 at a 10 km distance from the transmitting part. Signal attenuation store is 6 dB.