MODULATIONS

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MODULATIONS

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Parameters that characterize a modulation by radio equipment are shown in the following image:

modulation

In this dialog, if permissions are available, the user can configure advanced parameters of each equipment modulation:

Modulation Name.
Modulation type. Contains modulation and states number (QPSK, 64-QAM, etc.)
Mode. Indicates which operation mode of the radio equipment the modulation corresponds to.
Nominal power of transmitter for this modulation.
ATPC (Automatic Transmit Power Control). Margin en decibels for automatic power control, which will decrease rater power when it is possible to save energy.
Bitrate.

Threshold type:

oThreshold for 10-6 BER. It is the reception threshold for not exceeding a bit error rate for which seconds have many errors (segundos que de 10-6 medida con un tiempo de integración de un segundo).

oThreshold for a SES BER (Severely Errored Second). It is the reception threshold for not exceeding a bit error rate for which seconds have many errors (seconds with ≥ 30% of blocks with errors or at least one defect). This threshold depends on the digital frame structure sent in the radio link; Therefore it is not usually supplied by the manufacturer.

Type of spectral efficiency according ETSI (ETSI EN 302 217-2-2). If there are not network filters, masks defined in these standards are used.
Specification Method of the signature. Depending on parameters provided by the manufacturer, it could be specified by:

oK value, which is calculated from width and depth signature values and the reference delay, in addition to:

K signature value for minimum phase.

K signature value for not minimum phase

calculus_k

oUsing DFM (Dispersive Fade Margin), whose value is calculated according to the following formulas:

calculus_DFM_graph

calculus_DFM

It indicates if cross polarization canceller is applicable in the modulation, indicating its Cross-polarization Improvement Factor (XPIF) in dB.

 

In addition, the modulation dialog also has a C/I section where the user can indicate:

relación Carrier / Interference ratio calculation:

oCo-channel SES C/I, to ensure SES BER with a degradation of 1 dB threshold.

oAdjacent SES channel C/I, to ensure SES BER with a degradation of 3 dB threshold.

o3dB SES Co-channel C/I,  to ensure SES BER with a degradation of 3 dB threshold. It is the margin which indicates whether a co-channel signal will interfere.

o10-6 BER Co-channel C/I , to ensure 10-6 BER with a degradation of 1 dB threshold.

oAdjacent 10-6 BER channel C/I, to ensure 10-6 BER with a degradation of 3 dB threshold.

o3dB 10-6 BER Co-channel C/I, to ensure 10-6 BER with a degradation of 3 dB threshold. It is the margin which indicates whether a co-channel signal will interfere.

C/I mask, or protection factor. It can be edited manually. It is the result of the transmitter emission filter and the receiver selectivy filter convolution in the same equipment with same modulation. Typically known as NFD (Net Filter Discrimination).