RF Central RFX-BRK Especificações descarregar pdf (Página 11)

RFX-BRK Issue 1 page 11 of 19

• DC Power Supplies

DC/DC converters are used to generate the various supplies from the incoming

9-18V battery supply. These include 2.5, 3.3V, 5V, 8V and 1.2V.

5.2 COFDM Modulator

The normal scheme of COFDM modulation adopted by RF Central for the RFX-BRK is 2k

carriers with 8MHz RF band-width.

The COFDM modulator has been designed to take its input from the MPEG2 encoder.

This Transport stream is then modulated directly to the output frequency band (e.g. 2GHz).

This method reduces the occurrence of inter-modulated harmonic frequencies, requires

less upconvertors, and results in a smaller size for the RFX-BRK transmitter.

The modulator is automatically configured to match the data rate of the MPEG2 Encoder

as defined by the selected parameter set. See paragraph 6.2

5.3 Power Amplifier

The function of the power amplifier is to amplify the signal from the COFDM modulator to a

suitable level for transmission via the SMA-type connector into the antenna. The amplifier

is required to be highly linear to accommodate the multiple carrier signal formats employed

for digital system operation, with very low distortion (low inter-modulation between

carriers). The nominal output power is +20dBm (100mW) (band specific)

The status of the PA is provided by an LED to monitor RF output level (blue), see

paragraph 6.1

5.4 Maintenance of the RFX-BRK

To ensure good RF practice, when power is applied to the RFX-BRK, always make sure

that there is a suitable load or antenna connected to the RF output.

There are no field replaceable parts on the unit PCB. If a fault occurs with the board,

please contact RF Central for technical assistance.

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RF Central RFX-BRK Especificações Página 11