Data Sheet

K-MC4 MONOPULSE RADAR TRANSCEIVER Datasheet
Using VCO and IF Outputs
The IF amplifier provides two outputs per channel according to Fig. 1. These outputs are designed for
different requirements in processing radar signals. Both I (imaginary) and Q (real) mixer signals are
available. The I and Q signals are phase shifted by +90° or -90°, depending on the moving direction of
objects in range. I1 and I2 (and Q1 and Q2) signals are phase shifted by the object deviation from the
normal axis (refer to chapter Fig. 3 ).
FMCW generates an output signal even without an object in range because of the finite isolation
between transmitter and receiver path. This effect is called self-mixing and leads to a DC signal that
depends on the carrier frequency.
Example showing a single target:
Triangle VCO Amplitude: 8Vpp
Triangle period T
M
= 14ms.
Modulation depth f
M
=
160MHz
IF output freq. f
b
= 450Hz
I_AC and Q_AC outputs show a low
frequency caused by local carrier
feedthrough.
The superposed higher frequency f
b
is often called beat frequency,
caused by a target at a distance of
about 3m.
Fig. 7: Ix and Qx Output FMCW signals with triangle VCO and df = 80MHz
Distance calculation
R=
c
0
2
f
b
f
M
T
M
2
= 3m approx
For legend refer to Fig. 7
R Range, distance to target
c
0
Speed of light (3 * 10
8
m/s)
Please contact RFbeam Microwave GmbH for more informations on FMCW and also on FSK
applications
Ix and Qx IF Outputs
These outputs provide amplified low noise signals generated by doppler effects or FMCW. They
directly can drive ADC input stages of microprocessors or DSPs. Even with 10Bit of resolution only,
sensitive and relatively long range Doppler detections are possible. The outputs cover a frequency
range of 15Hz ... 300kHz.
12Bit ADConverters are recommended for higher sensitivity to get optimal resolution for filtering and
signal processing.
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