IGEP
TM
RADAR SENSOR ORION Hardware Reference Manual
ISEE 2007
S.L. All rights reserved, IGEP™ is a registered trademark from ISEE 2007 S.L. The following is provided for informational purposes only.
DOCUMENT FROM ISEE 2007 S.L. Ref: MAN-PR-RADR0010-RA1-001
32
9
BASIC RADAR THEORY: IF SIGNAL BANDWIDTH
The IF Radar signal will be of some KHz bandwidth, depending on the modulation sweep time
and RF signal bandwidth.
The next equation gives the relation between the target distance and its corresponding IF
frequency, in case of linear frequency modulation:
hzpm [Hz/m]=2*BW[Hz]/V[m/s]*T[s]
(IV)
Where:
BW
: RF output frequency bandwidth
V
: media electromagnetic wave propagation speed (3*10
8
m/s by default).
T
: FM linear Modulation sweep time.
For example, if we consider SLOPE=51 and NINC=FFF, then T=6634us.
With these values and considering a modulation bandwidth (BW) of 1GHz, then we obtain:
hzpm=1005.
If we want to detect a target at a maximum range of R=40m, then the IF bandwidth will be:
F
MAX
= R * hzpm = 40 * 1005 = 40,188KHz.
(V)
As the IF hardware filter is fixed between 3 and 32 KHz we will have to change modulation
parameters in order this signal “can be seen” by the radar.
We could change for example the SLOPE parameter to 'A0' value then the modulation sweep
time will be higher: T=13104us, thus resulting on a new hzpm parameter: hzpm=509, so now
the corresponding frequency for a target at 40m distance will be: 20,345 KHz, that fits within
the 32KHz fixed IF Filter Radar Hardware, so now the radar “will see” the target.
In this example we can see the power of Modulation programming: we can extend or comprise
the range of the radar at our choice.
