JVC TDR6 Output Spectrum Width, Eb/N0 Definition, Minimum and Maximum Information Rates

Information Rates

The minimum and maximum information rates are provided in the following table.

Minimum and Maximum Information Rates

Code Rate	1/2	2/3	3/4	5/6	7/8
Minimum Information Rate	0.92	1.23	1.38	1.54	1.61
(Mbps)
Maximum Information Rate	27.6	36.8	41.5	46.1	48.4
(Mbps)

Output Spectrum Width

To prevent intersymbol interference, the outgoing symbols are filtered by a DVB-compliant transmit filter. The filter type is a square-root raised cosine filter with roll-off factor alpha = 0.35. The result is that the output spectrum has a width of (1.35 * Symbol Rate).

The following table provides examples of information bit rates versus transponder bandwidth at each code rate.

Transponder	QPSK	QPSK	QPSK	QPSK	QPSK
BW (MHz)	1/2 Mbps	2/3 Mbps	3/4 Mbps	5/6 Mbps	7/8 Mbps
54	36.8627	49.1503	55.2941	61.4379	64.5098
46	31.4016	41.8668	47.1024	52.3360	54.9528
41	27.9884	37.3178	41.9826	46.6473	48.9797
36	24.5752	32.7669	36.8627	40.9586	43.0065
33	22.5272	30.0363	33.7908	37.5454	39.4227
30	20.4793	27.3057	30.7190	34.1322	35.8388
27	18.4314	24.5752	27.6471	30.7190	32.2549
18	12.2876	16.3834	18.4314	20.4793	21.5033

Estimating Eb/N0 The TRD6 provides an estimate of the Eb/N0. To access this estimate:

■Using the front panel, select Details>Input>Status>Eb/N0

■Using a remote unit, issue the command DMD.x EBNO

Eb/N0 Definition

The Eb/N0 expression is defined as follows:

■Eb = Energy per information bit.

■N0 = Noise energy per Hz.

The formula for Eb/N0, in dB is:

Eb/N0 = C(dBm) - N0(dBm/Hz) - 10log(IR) where:

■C = Carrier Power

■IR = Information Rate

Demodulator Application Notes 01-0870-401B 01/03 83