RFbeam Microwave ST200 User manual

ST200 Radar Evaluation System
User Manual
© RFbeam Microwave GmbH www.rfbeam.ch January 2013 age 1/27

ST200 Evaluation System User Manual
Features
•Supports Doppler, FMCW, FSK, Monopulse
•USB Interface to Host Computer
•Onboard Low Noise ower Supplies
•Connectors for Different Radar Devices
•Amplifiers for Native Doppler Transceivers
•High erformance 16Bit Data rocessing
•250kSamples/s ADC and DAC
•Compact and Rugged Construction
•owerful Signal Explorer C Software
•NI LabVIEW ® DAQmx USB Interface
Applications
-Evaluation of Advanced Shortrange Radar Applications
-Development of Own Data rocessing Algorithms
-Signal Analysis and Logging
-Learning and Exploring Radar Basics
Description
ST200 is a 16Bit data acquisition and processing system with a total 250k/s sampling rate. It contains
all hardware necessary for acquiring Radar signals of RFbeam Transceivers.
ST200 contains a motherboard with power supply, amplifiers and I/O connectors. Data acquisition is
performed by a NI-USB-6211 16Bit multifunction DAQ module from National Instruments mounted on
the backside.
The easy to handle RFbeam Signal Explorer software features many basic Radar functions including
an exciting FSK (Frequency Shift Keying) operation mode for high resolution distance measurements
of moving objects.
ST200 Block Diagram
Radar Connectors:
X1: General purpose I/O
X2: Mixed I/O
X3: 4 Channel An. Inputs
X4: 2 Channel An. Inputs
X5: 2 Channel An. Inputs
Computer Interface:
X9: USB C ort
ower:
X10: Optional DC In
X11: Low Noise DC Out
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ST200 Evaluation System User Manual
Getting Started
Please install so tware prior to connect ST200 to the USB port.
Equipment Needed
•ST200 Hardware
•ST200 Signal Explorer Software Installer on CD, USB stick or downloaded on HD
•USB cable
•K-LC2 sensor connected to connector X5
•C running on Windows xp or never
Installing Signal Explorer So tware
ST200 software comes with a setup procedure containing all necessary components into one single
package:
•RFbeam ST200 Signal Explorer Software
•National Instruments DAQmx ® driver software
•National Instruments LabVIEW ® runtime systerm
1. Start RFbeam Signal Explorer setup.exe from your intallation media
If your computer does not already contain a LabVIEW runtime engine and DAQmx driver, you
will be prompted to accept licences of National Instruments.
2. If possible, accept all default program locations. Troubleshooting will be simplified like this.
3. lease be patient while LabVIEW runtime system and DAQmx driver are being installed.
This may take some minutes...
4. Restart your computer, if asked so.
5. You will find SignalViewer under START-> ROGRAMS->RFbeam->Signal Explorer and a
shortcut icon on the Desktop.
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ST200 Evaluation System User Manual
Test Con iguration and Go!
We will now take a first impression by using the Doppler mode and observe movement of persons.
lease refer to the screen shot in Fig. 1
1. lug in a K-LC2 radar sensor into connector X5 of the ST200.
2. Connect ST200 hardware to you computer. There should appear a “New USB Hardware
Found” message from Windows.
3. Windows will probably ask you for a hardware driver. Select to find it aoutomatically.
4. Start SignalExporer under START-> ROGRAMS->RFbeam->SignalExplorer
After some seconds the main screen of the Signal Explorer should appear.
5. Select the most important controls according to Fig. 1 below.
6. Drag all 3 cursors as shown in Fig. 1 . If cursors are not visible, press cursor "Reset" button.
7. Now move your hands in front of the K-LC2 sensor. You will see the frequency and speed in
the upper graph and the time signal (oscilloscope) in the bottom graph.
8. Explore and become familiar with the effect of the 3 cursors.
9. Try to switch to Doppler- hase screen by using the left tab in the bottom half of the screen.
You will see the direction of your movement (Cursors must be set according to Fig. 1 ).
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Fig. 1: Start Screen. Try to set all marked controls according to this igure
Y-range
Sensor configuration
Logarithmic display
Channel for FFT
Reset cursors to
visible area
Y-range
Channels to show
Detection area
defined by 3 cursors
Filter settings for time
domain
Time domain modes

ST200 Evaluation System User Manual
ST200 Hardware
ST200 consists of a mother board and a 16 Bit USB data acquisition system with 250kHz sampling
rate. The mother board contains 5V and 3.3V low noise power supplies and analog buffers and
amplifiers.
Sensor Connectors:
X1: General purpose I/O
X2: Mixed I/O
X3: 4 Channel An. Inputs
X4: 2 Channel An. Inputs
X5: 2 Channel An. Inputs
Computer Inter ace:
X9: USB C ort
Power:
X10: Optional DC In
X11: Low Noise DC Out
Fig. 3: Block Diagram
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Fig. 2: Connector Arrangement
X1 X2 X3 X4 X5
X9
X10
X11
J 1 -> X1
3.3V / 5V
J 2 -> X2
Dig. I/O
J 3 -> X2,3
3.3V / 5V
J 4 -> X4,5
3.3V / 5V
ower Supplies
FM Level Shifters re-Amps

ST200 Evaluation System User Manual
Typical Sensor Connections
lease refer to Fig. 3 and to chapter Sensor Connectors for more details on tzhe connectors.
Sensors with higher current consumption (>120mA like K-MC4) need more power than USB can
deliver.
An external DC 12V power supply with >0.5A should be plugged into X10 of the ST200 system.
K-LCx Series → X5 or X4
Sensors of the K-LCx series with no internal amplifiers can directly be plugged into X5.
For remote connecting K-LCx sensors, a 6 pin ribbon flat cable my be connected to X4.
X5 or X4 provide 2 channels with amplifiers.
K-MCx and K-HC1 Series → X3
K-MCx sensors provide internal amplifiers and are typically connected to X3.
X3 provides 2 channels and is directrly routed to the DAQ system.
Notes:
- K-HC1 needs an own, separate power supply and a special adapter cable.
- K-MC4 can only be operated with an external 12VDC power supply connnected to X10.
Other Sensors
lease contact RFbeam for instructions on connecting special sensors.
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ST200 Evaluation System User Manual
Signal Explorer So tware
Overview
Getting Help
Most controls and readouts provide a context help on mouse over.
Select Help - Show ContextHelp from main menu. This opens a floating window containing a brief
description of the object pointed by the mouse cursor.
Operation Modes
ST200 Signal Explorer provides 3 main operation modes:
•Doppler Mode: Speed and direction measurements
•FMCW Mode: Distance measurements of statical and moving objects
•FSK Mode: Distance measurements with high resolution for moving objets
User interface includes selecting of operation modes and sensor types, setting of filter types and
bandwidth, sampling rates, graphical representation of signals in time and frequency.
User inteface screen is devided into 3 sections:
Fig. 4: Screen Sections
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General Section
Operation Section
Recorder Section

ST200 Evaluation System User Manual
General Section
Settings and readouts in the general screen section (see Fig. 4) are accessible in all operation modes.
Readouts
Samples: Number of samples per channel as input for the signal processing (FFT).
Rate: ADC sampling rate per channel.
Loop Time: Time to read the samples defined in the selected configuration. It is calculated by
Con igurations Selector
Many key settings are stored as so called configurations. Existing configurations may be selected at
any time. After selecting, Signal Explorer jumps back into operation mode Doppler.
Configuration naming convention:
K-LC2_X4-5_IQH.cfg
| | |_ connector inputs
| |____ connector name(s (refer to chapter Sensor Connectors
|__________ sensor type
Con igurations Setup
You may alter or copy existing configurations. New configurations may be generated.
Refer to chapter Settings for more details.
Operation Section
This is the real time signal section (see Fig. 4).
Select the operation mode with the horizontal tabs on the top. Some modes allow selecting sub-modes
by the vertical tabs in the bottom left part of the operation section.
Recorder Section
ST200 Signal Explorer allows real time recording and playback of signals captured in the Doppler and
in the FSK mode.
© RFbeam Microwave GmbH www.rfbeam.ch January, 2013 age 8/27
looptime=number of samples
samplingRate

ST200 Evaluation System User Manual
Using Signal Explorer So tware
Doppler Mode
About Doppler Radar
A more precise tiltle would be 'CW (Continuous Wave) Doppler Radar', when using RFbeam Radar
sensors. These sensors do not produce pulses, but send continuously in the K-band (24.125 GHz ).
The sensors are also called Radar transceivers, because they include a Transmitter and a Receiver.
Doppler Radar is used to detect moving objects and evaluate their velocity. More details on the
principle can be read here:
http://en.wikipedia.org/wiki/Doppler_radar
http://www.radartutorial.eu/11.coherent/co06.en.html
RFbeam Radar transceivers return a so called IF signal,
that is a mixing product of the transmitted (Tx) and the
received (Rx) frequency. An moving object generates a
slightly higher or lower frequency at the receiver. The IF
signal is the absolute value of the difference between
transmitted and received frequency.
These transceivers operate in the CW (Continuous Wave)
mode as opposed to the pulse radars, that measure time
of flight. CW radars can operate with very low transmit
power (< 20dBm resp. 100mW).
Calculating the Doppler requency
fd=2⋅fTx
⋅v
c0
⋅cos α
(1)
or
v=c0
⋅fd
2⋅fTx ⋅cos α
(2)
fd Doppler frequency
fTx Transmit frequency (24GHz)
c0 Speed of light (3 * 108 m/s)
vObject speed in m/s
αAngle between beam and object moving direction
At a transmit frequency of fTx = 24.125GHz we get a Doppler frequency for a moving object at the IF
output of
fd=v[km/h]⋅44Hz⋅cos α
or
fd=v[m/s]⋅161Hz⋅cos α
(4)
Angle α reduces the measured speed by a factor of cos α.
This angle varies with the distance of the object.
To evaluate the correct speed, you need a trigger criteria at a
known point. This can be accomplished by measuring the
distance with the radar sensor (e.g. using FSK technology) or
by measuring the angle using a monopulse radar such as
K-MC4.
© RFbeam Microwave GmbH www.rfbeam.ch January, 2013 age 9/27
Fig. 6: De inition o angle α
αmoving
object
Radar sensor
Fig. 5: Typical Radar Transceiver
K-LC1a
Tx Rx
IF output
FM Input

ST200 Evaluation System User Manual
ST200 Doppler Mode
Note the difference between logarithmic (upper figure) and linear (bottom figure) FFT display. Smaller
peaks in logarithmic display disappear in linear display.
Note the difference: in linear mode, small signals and noise disappear.
Remember to reset cursors after switching between logarithmic and linear mode.
© RFbeam Microwave GmbH www.rfbeam.ch January, 2013 age 10/27
Fig. 8: Linear FFT scale
Linear display
Fig. 7: Logarithmic FFT scale
Logarithmic/Linear
display
Cursor low freq. limit Cursor high freq. limit
Low amplitude limit
Reset cursors to visible
area
Filter for time signal
bandwidth