User's Manual

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Band Microwave Motion Sen
sor Module
HB170 Users Manual
V1.0
0
ST Electronics (Satcom & Sensor Systems) Pte. Ltd.
29 New Industrial Road, ST Electronics Paya Lebar Building, Singapore 536213
Tel: [phone] Fax: [phone] Email: [e-mail]
Website: www.ag
ilsense.com (
Regn
:
199103901W
)
The 93dB loss is the total losses combining two ways free space loss (82.4 dB for 30 meters at 10.525
GHz), reflection loss and absorption loss of the target, as well as other losses.
This RSS figure can be viewed as an approximation of the output signal strength for a human at 15
meters away walking straight to the module at 1.28 km/hour.
Reflection of a human body is varied with the size of the body, clothing, apparels and other
environmental factors; RSS measured for two human bodies may vary by 50%.
Circuit designer must take note of the maximum and minimum Received Signal Strength (RSS)
specified in technical data sheet, when designing the amplifier. Sensitive deviation between modules
has to be considered when setting amplifier gain or alarm threshold. On-production-line gain
adjustment may be necessary if a narrow window for triggering threshold is required.
Noise - The noise figure specified in the technical data sheet is the noise measured in an Anechoic
chamber, that shields the unit-under-test from external interference, as well as reflections from surfaces.
Hence, the figure is only representing the noise generated by the internal circuit itself.
Other than noises generate from internal electronic circuit, in actual applications, other noises may be
picked up from surrounding, or other part of the electronic circuit.
Special attention has to be given to the interference picked up from fluorescent light, as the 100/120 Hz
noise is closed at the Doppler frequency generated by human movement.
On and off switching of certain devices (relay, LED, motor, etc.) may generate a high magnitude of
transient noise at the IF terminal. Careful PCB layout and time masking is necessary to prevent false
triggering.
DC Level - DC level (0.01 to 0.2 Vdc) exists at the IF terminal and its polarity can be positive and
negative. Its magnitude may vary over temperature. AC coupling is recommended for IF terminal
connection.
8. Radiation Safety
Microwave radiation from the module is well below established safety standards for general public
environment, like ANSI C95.1-1991 of USA and NRPB-G11 of United Kingdom.
9. Handling
The module has been fully tested to specifications. Upon opening, tighten or loosen the chassis will
cause performance deterioration.
The module is an electrostatic sensitive device (ESD). Precautions shall be observed for handling and
assembly.