User's Manual

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MSAN
-
008
K-Band FMCW Transceiver DF Modules
Application Note
V1.0
1
ST Electronic
s (Satcom & Sensor Systems) Pte Ltd
1 Ang Mo Kio Electronics Park Road, #06-02, ST Engineering Hub, Singapore 567710
Tel: [phone] Fax: [phone] Email: [e-mail]
Website: www.agilsense.com ( Regn. No.: 199103901W )
Stationary Object
For stationary object, simple sawtooth shape frequency sweeping is suggested as there is no
requirements for measuring velocity. By varying tunning voltage , user will be able to obtain plot of
frequency versus time.
The solid line indicates transmitting signal while the dashed line indicates received signal from object.
As can be seen, there is a frequency difference f

between transmitted and received signal due to time
delay introduced by signal propagation in air.
Distance between sensor and detected object can be calculated based on formula:
k
fc
R




2
Where
R: Distance between sensor and object.
c: speed of light in freee space, 3*10
8
m/s.
f

: frequency difference between sent and received signal.
k
: gradient of frequency change.
Please refer to Annex 2 for more detailed FMCW stationary object range calculation.
Figure 4: Detection of Stationary Object
Received signal
Transmitted signal