User's Manual

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MSAN
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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 )
Moving Object
For detection of moving object, the triangle wave is suggested in order to obtain information on
distance and velocity ( Figure 5).
Figure 5: Detection of Moving Object
The solid line in figure 5(a) indicates transmitted signal while the dashed line indicates reflected
signal.The soild line in figure 5(b) stands for absolute value of frequency difference between
transmitted signal and received signal.
Note: Typically, computation of data takes place for period that generates stable f
if+
and f
if-
;
transition period is normally avoid.
By varying tuning voltage, user is suggested to increase frequency linearly from
b
f (base frequency) to
Bf
b
 (bandwidth) in half T (period) time and then decrease frequency linearly back to
b
f in another
half T time. Compared to stationary object, moving object’s received signal not only has time delay
which introduces
R
f , but also has upper or lower displacement due to the doppler frequency
d
f .
Transition
Period
f
if+
f
if-
d
f
Received signal
Transmitted signal