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RFbeam Microwave GmbH | Schuppisstrasse 7 | CH-9016 St. Gallen | www.rfbeam.ch | K-MD2 Engineering Sample | data sheet

07/2018 – Revision A | Page 6/23

THEORY OF OPERATION

The K-MD2 is configured to perform Frequency Mo-

dulated Continuous Wave (FMCW). With this modu-

lation the radar receives information about static and

moving objects.

In a typical FMCW radar system, the carrier frequency

is modulated with a digitally generated linear ramp. At

each step in the ramp, the received signal is demodu-

lated and the phase is sampled.

4 samples ignored

256 samples used

bandwidth

f

t

Frame

The K-MD2 is configured to sample 257 chirps per

frame but disregards the first chirp and uses only 256

chirps. Ignoring the first chirp is necessary to exclude

disturbances in the first chirp which are caused by

jumping to the start frequency.

First chirp ignored

256 chirps used

f

t

Chirp 0

Chirp 1

Chirp 2

Chirp 256

Figure 7: Frame generation

Figure 6: Ramp generation and sampling

Ramp

The K-MD2 is configured to use a saw tooth modula-

tion for the ramp. It samples 260 points and ignores

the first 4 samples. This means only the last 256

samples are used for processing. Ignoring the first

four samples will be done to eliminate the discontinui-

ty at start of the ramp.