©

RFbeam Microwave GmbH | Schuppisstrasse 7 | CH-9016 St. Gallen | www.rfbeam.ch | K-LD2 | data sheet

09/2018 - Revision B | Page 5/20

Overview

The K-LD2 takes advantage of an internal I/Q doppler

signal processing by using a complex FFT (Fast Fou-

rier Transform). The main advantages of this proces-

sing compared to standard time domain processing

solutions are the following:

– Easy detection of the direction of a movement

– Increased detection range with better SNR

due to the FFT processing

– Efficient interference suppression

– Vibration suppression

Sampling & FFT calculation

– I/Q channel

– Configurable sample rate

– 256 point complex FFT

Threshold generation

– Adaptive noise measurement

– Interference suppression

– Depending on sensitivity setting

Detection algorithm

– Search for valid detection

– Direction, speed & magnitude

calculation

– Latch detection for the length

of the hold time setting

Figure 4: Signal processing and detection workflow

With a powerful command set (See chapter Command

Set Description) it is possible to configure the  whole

signal processing and detection workflow. This allows

customisation of the K-LD2 to get the best results in

different environments and applications.

THEORY OF OPERATION

The signal processing unit samples the analogue

I/Q doppler signals of the RF frontend and calculates

a  complex FFT in real time. In a next step an adap-

tive noise measurement and interference suppression

is done which generates a threshold limit that can be

adjusted with the sensitivity setting. Then the detection

algorithm looks for a valid detection and latches it to

the detection register and the digital outputs for the

length of the hold time setting.