Modulator Menu Explained

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Modulator Menu Explained

 

Menu Title

Default

Description

Country

U.K

Country will be determined by TV country of operation

Channel

CH60

Channel number

Freq (Khz)

786000

Channel Frequency will correspond to channel number

BW (MHz) - Bandwidth

8

Bandwidth of the sub carrier

Constellation

64QAM

Quadrature Amplitude Modulation

Type of modulation for digital signals (DVB-C and -T).

Two signal components I and Q are each quantized and modulated onto two orthogonal carriers as appropriate for the QAM level (4, 16, 32, 64, 128, 256). The constellation diagram is obtained by plotting the signal components with I and Q as the coordinate axes.

Therefore, 2, 4, 5, 6, 7 or 8 bits of a data stream are transmitted with one symbol, depending on the QAM level (4, 16, 32, 64, 128, 256). This type of modulation is used in cable systems and for coding the COFDM single carriers.

FEC - Forward Error Correction

7/8

Code rate:1/2, 2/3, 3/4, 5/6, 7/8

Used to trade bit rate versus ruggedness, e.g. the signal strength required and interferenceprotection required

FFT - Fast Fourier Transform

8K

The DVB-T standard defines two FFT modes to constitute the OFDM signal:

2K – 2048 subcarriers

8k – 8192 subcarriers

Guard in - Guard Interval

1/32

The guard interval is a proportion of the time there is no data transmitted between the symbols

RF out - Power Output

-31 dBm

The output power should be balanced to obtain a good signal at the receiving unit