Relay Compositions of DTV Relay Stations

(Product code: 6565JA)

Outline

This is 50W SCPA for the relay station of ISDB-T Digital Terrestrial Broadcasting. A low warp and the high stability have been achieved by adopting feed forward method as distortion compensations. Because the band of 24MHz is secured, 4ch or less can be amplified at the same time.

Structure

JIS rack mounting type
External size: 480(W) x 149(H) x 500(D)mm (Excluding protrusions)
Mass: 35kg or less

Specification

(The I/O level is a mean value.)

Input	Band width	4 specified continuous channels between 470MHz to 770MHz
	Impedance	50Ω/TNC type (Unbalance)
	Level	-10dBm
Output	Band width	Same channel as input
	Impedance	50Ω/TNC type (Unbalance)
	Standard gain	+57dB
	Standard level	50W (4 OFDM wave of a specified channel)
	Monitor	-47dB±1dB against output level
	Monitor connector	BNC type J
Power supply voltage		DC+48V±15% or less
Power consumption		700W or less
Environmental requirements	Temperature	-10°C to +45°C (Range for in-spec)
		-20°C to +60°C (Range for spec restorable)
	Humidity	45% to 90%RH (Without dew.)
Cooling method		Forced air cooling
Use conditions		Continuous use

Performance

I/O VSWR	1.2 or less(Do not destroy by shorting or opening the input-output terminal.)
Amplitude-frequency characteristics	0.5dBp-p or less(Within using band)
IM	-50dB or less (When 4 OFDM wave 5W is output)
Changeable gain range	-6 dB or less from +2 dB or more finishes must being changeable compared with 5W.
Output fluctuation	Within ±0.5dB in the performance guarantee temperature.
Alarm monitoring item / Meter output-Meter rating Full scale 300mV
Power failure	Each DC voltage of power supply part is observed and warning is output by the change of ±20% or more.
Output abnormal	When the output becomes following the setting, warning is output.
PA abnormal	Each FET current are observed and When it changes to -30% or less of idol (current at a no signal), or to +30% or more of the current outputs ratings, the FET current is intercepted; warning is output, and maintained.
FAN abnormal	When fan is stopping, or becoming 700mi-1n or less (designed value), warning is output.
Temperature abnormal	When the FET temperature becomes +85°C, the FET current is intercepted; warning is output, and maintained.
Compensations abnormal	When the internal compensations circuit power supply is off, or the state of IM is continued 40dBc±3dB for two seconds, warning is output.
Pilot abnormal.	When abnormality occurs in the compensations circuit pilot signal, warning is output.
Power supply	96mV is output to 1.5k load when +48V.
FET current	60mV is output to 1.5k load when 10A.
Output level	200mV is output to 1.5k load when ratings are output,
Alarm interface	Non-voltage contact output Contact rating DC24V, 0.1A or less (ALARM) D-sub 15S M2.6 screw

Function

This equipment is a power amplifier for multichannel that amplifies the OFDM signal up to four waves or less to regulated transmitting power at the relay station of ISDB-T Digital Terrestrial Broadcasting.
This feature is that a low warp and the high stability have been achieved by adopting feed forward method as distortion compensations.
It provides with the watch and the control operation in accordance with the transmission equipment commonness specifications for the digital terrestrial broadcasting (Orange Book), and it is possible to connect it with the PA switch control equipment etc. Moreover, it has the function to output the output level, the power-supply voltage, and the FET current as DC voltage to display it to the meter.
Steady operation is possible, because the fan for the forced air cooling that can be exchanged is installed at front side, and the inside design is considered the ventilation efficiency.