2x50w VHF/UHF Transmitter relays TV signals received from satellite using TVRO incorporating 2 No's of C Band TVRO Units switchable between national and regional service. At a time one 50W VHF/UHF Transmitter will remain ON.

The design incorporates the latest technology based on MOSFET technology to provide the best possible reliability and ease of maintenance and low power requirement.

The system consists of

1] Two no's of 50W Transmitter incorporating Class-AB amplifier
2] An Automatic Switching Unit ( A.S.U.)

The transmitter will be energized by ASU when an incoming signal is present. ASU will also automatically change over to the healthy unit whenever there is fault in any Exciter Or P.A .Unit. All the equipment should be rack mounted.

The transmitter is capable of Unattended operations.

The equipment conform to CCIR Standard - PAL -B/G colour .

i] Operating temperature: (-10 degree C to + 50 degree C )

ii] Relative humidity up to 98 %

iii] Altitude up to 3000 mtr above MSL.

A.VISION SECTION:
1. Power output 50W ( Sync Peak )
2. Input Impedance 75 Ohms
3 Input Return loss 30 db upto 6 Mhz
4. Video Input level 1V( p-p) adjustable (with 0.3V
sync)
5. Hum rejection 26 to 30 db

7. FREQUANCY RESPONSE ( as per CCIR-B/G standard)
- 4.43 MHz -30db
-4.43 to 1.25 MHz -23db
-1.25 to - 0.75 MHz +0.5 db
- 0.75 to 4.5 MHz +0.5db to - 0.5db
+ 5.0 MHz +0.5db to - 2.5db
+ 5.5MHz -25db

8. Differential gain +/- 3 %
9. Differential Phase +/- 3 degree
10. 50 Hz square wave response +/- 2 %
11. Bar tilt (2T pulse shape
20T response ) +/- 2 %
12 Vision signal to noise ratio a. Better than 56 db compared to black level un weighted
b. Better than 60 db weighted
13 Group Delay less than or equal to +/- 50 ns
14 Possible group delay 300ns
correction.

15. Indication
· LED indication of video presence in Video Processor module should be provided.
· LED for APC fail should be provided.
· Modulation depth metering indication in Vision Modulator should be provided.

16. Frequency stability 200 Hz in 3 Months independent of source

17 Harmonic emission and
spurious radiation. -60 dbc below carrier .

18. Inter Modulation Products equal to or better than 54 db
( Vision - 8db sound - 10db
sub carrier - 16 db }
19. Power requirements i] system should work on 24V DC derived from solar charge battery system

ii] It should incorporate Mains operated battery charging system capable of automatic Mains change over when Solar energy is not available OR Batteries are not charged to adequate capacity

iii] Power consumption for VHF/UHF should be less than 415 W
iv] Efficiency of DC-DC converter should be better than 80%

20. Sync pulse Compression Less then 3 %

21. ALC Less then + 0.5 db output variation with 3db change in amplifier Gain

22. AM due to FM 1 % Maximum
Less then 1% [ 46 Db ]
From 50Hz to 15 KHz.

23. RF Output Impedance 50 Ohms

1. Type of Emission F-3E

2.Power Output 5W

3.Input level - 5dbm to +12 dbm
into 600 ohms balance load

4. Frequency Response + /- 0.5 db from 20KHz to 15 KHz

5. Distortion Less then 0.5% at 50Khz deviation
6. Pre emphasis 50 Micro seconds
7. S/N Ratio- Un weighted 54 db
8 S/N Ratio - weighted 60 db.
9. Indication
· Metering indication of frequency deviation
in Aural Modulator should be provided.

The automatic switching unit plays a vital role in Unattended Dual 50W VLPT which are to be installed in Remote areas. It is to carry out the following functions;

A] To switch the transmitter 'ON ' automatically when satellite signal is available
B] To switch ' ON ' the right sub units of TV Transmitters as well as TVRO into operations and Switch OFF the remaining Units. to Conserve the power.

C] To provide Command Signals for audio / video switching between TVROS and Exciters, ALC, RF Signal switching between Exciters And power Amplifiers and RF Switching at antenna level.

D] To provide status information on the front panel. The status information should be Displayed on the Front panel through aesthetically well arranged LEDS. The status information consist of
1] TVRO -1 ON 2] TVRO-2 ON 3] Exciter-1 ON 4] Exciter -2 ON 5] P.A.-1 Power Amplifier-1 ON 6] P.A.-2 Power amplifier-2 ON 7] TVRO-1 failed 8] TVRo-2 failed
9] Exciter-1 failed 10] Exciter-2 failed 11] P.A.-1 failed 12] P.A.-2 failed 13] AC Mains failed.

E] To provide the status data to remote monitoring system for Transmission on telephone line OR satellite.

F] To provide Manual Operation of Transmitter for various combination of sub units.

1] Check points/ monitoring points shall be provided for checks at various stages of transmitter.

2]. Provision shall be made for connecting TV Demodulator where necessary for checking Quality of Picture and sound.

3] Provision for Transmission and Reception of control / Monitor and Telemetry signals to and from the transmitter for remote Monitoring Systems are essential.

4] Provision for Remote control and Monitoring facility for status of transmitter like
1] TVRO -1 ON 2] TVRO-2 ON 3] Exciter-1 ON 4] Exciter -2 ON 5] P.A.-1 Power Amplifier-1 ON 6] P.A.-2 Power amplifier-2 ON 7] TVRO-1 failed 8] TVRo-2 failed
9] Exciter-1 failed 10] Exciter-2 failed 11] P.A.-1 failed 12] P.A.-2 failed 13] AC Mains failed to be confirmed through the Satellite.