User manual

Code: ENIGMA III User Manual

Edition: 1 Revision: 4

Date: 19/12/2008

Page: 54/97

2. This multiple of the decimation factor must be in the range [1...20]

3. The decimation factor limits the minimal range gating. As a rule of thumb:

Smallest range gate possible is “decimation factor” * 2m. In other words. If

you want a minimum range gating of 25 m the decimation factor must not be

larger than 12 (which leads to 12*20=240 coefficients maximum which leads

to a filter length in time of 3.125µs)

Example:

A filter with 200 coefficients can be created with:

1. decimation 10 (10*20=200)

2. decimation 20 (20*10=200)

A filter with 80 coefficients can for example be created with:

1. decimation factor 8 (8*10=80)

2. decimation factor 4 (4*20=80)

3. decimation factor 5 (5*16=80)

4. decimation factor 16 (16*5=80)

FIRCoeff0 – FIRCoeff3

FIR coefficients for pulse 0...3 respectively

Format: FIRCoeffX <n> <C1I> <C1Q> <C2I> <C2Q> ... <CnI> <CnQ>

n - Length of the FIR filter (number of complex coefficients)

CnI, CnQ - n'th I and Q filter coefficient.

samplingFreq - Sampling frequency in MHz (76.8 MHz)

bandwidth - Passband bandwidth in kHz (Used by Frog only)

transition - Passband transition in kHz (Used by Frog only)

centerFreq - center frequency in kHz (16800kHz for 60MHz IF and 30000kHz for 30MHz)

windowType - Window type (Used by Frog only)

alpha - Window alpha (Used by Frog only)

GAMIC Proprietary