And Radio Technology

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RF Information Interchange

• And Radio Technology

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By Firas Faham, Senior Engineer
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RF Information Interchange
Introduction
Radio Frequency

• Information modulating SIGNAL m(t) is Audio,
  Video, or Data.
• RF modulated SIGNAL with carrier frequency f(c)
  helps the information travel.
• The RF SIGNAL s(t) represents the f(c) carrier
  providing a ride to m(t) and enabling RF wireless
  or wired communication, cellular, or point to
  point.
• S(t) x(t) Cos (2p fo) t - y(t) Sin (2p
  fo) t
• RF, Microwave, and Millimeter Wave.
• RF is less than 1 GHz.
• Microwave is between 1 GHz and 40 GHz.
• Millimeter wave is greater than 40 GHz.

Easy
Fun
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Frequency allocation
30-300 Hz 10-1Mm .....ELF (extremely low
frequency) 300-3000 Hz ..........................
...............1Mm-100 km 3-30 kHz 100-10 km
...........VLF (very low frequency) 30-300 kHz
10-1 km .....................LF (low frequency)
300-3000 kHz 1 km-100 m ....MF (medium
frequency) 3-30 MHz 100-10 m ....................
HF (high frequency) 30-300 MHz 10-1 m
..........VHF (very high frequency) 300-3000 MHz
1 m-10 cm ..UHF (ultra high frequency) 3-30 GHz
10-1 cm .............SHF (super high frequency)
30-300 GHz 1 cm-1 mm EHF(extremely high
frequency)
Wavelength cm 30 / frequency GHzFrequency
GHz 30 / Wavelength cm1000 MHz 1
GHzWavelength mm 300 / Frequency GHz (for
sub-mm)Wavelength um 300,000 / Frequency
GHz (for Scuba and others)
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Access

• Distance and power control, for wireless.
• Selection (Frequency selector networks and Time
  selector
• networks.)
• Multi-users enhanced security (TDMA, DS or FH
  SS, and CDMA.)

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Technologies
Logic Trunk Network automatically assigns one
channel from the pool of channels to one
user. TDMA Time division multiple access. FDMA
Frequency division multiple access. Blue Tooth
an open standard for short-range transmission of
digital voice and data between mobile devices
(laptops, PDAs, phones) and desktop devices. It
supports point-to-point and multipoint
applications. SS Spread spectrum is a form of
wireless communications in which the frequency of
the transmitted signal is spread or varied over
greater bandwidth than the un-spread
signal. Packet Networks The fragments of the
message are exchanged in sequence between
terminals according to certain rules (protocols.)
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Encoding
on the go
0 1 1 0
RZ NRZ PPM PWM
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Modulation
AM Carrier 540 TO 1700 KHz. 117 channels each
of 10 KHz BW.
FM Carrier 88 to 108 MHz. 100 channels each of
200 KHz.
DS SS
FH SS
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2 Way communication
SUPERHETERODYNING
IF frequnecy is obtained by up or down conversion
of input signal frequency.
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Making the choice
High performance, scalable, and back ward
compatibility. Standardization (ISM band, other
manufacturers, IEEE, FCC) Environment and
interference (Location, close by
systems) Security and integrity (multiple
access, jamming, multi path interference) Speed
and access media. Network connectivity. Technolog
y (functionality, ease of use, Shared or
dedicated channels, Wide or Narrow Band) Cost
(upgrade, expand, or new system.)
FCC
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What can we do with it?
Sensormatic

• RFID, Source tagging, EAS, Transponders,
  surveillance, and theft-prevention systems
• CATV and MMDS.
• Remote monitoring and control.
• Wireless communication, Pagers and cellular
  phones .

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Alarm systems
EAS
Loss prevention
Electronic Article Surveillance
Record keeping
According to AIM (Association of Automated
Identification Manufacturers) over 80,000 EAS
systems are installed world wide resulted in
saving of millions of dollars for retail industry.
Increased sales
Reduced labor
Inventory
Identification

• Different exit/ Entrance aisle width.
• Consumer Products Manufacturers Association
  (CPMA) encourages manufacturers to produce
  compatible tags.
• Types are AM Acousto Magnetic, EM Electro
  Magnetic, Swept RF, and Microwave system.
• Acousto Magnetic AM system has the advantage of
  attaching tags directly on metal surface.
• System type and surveillance area width are
  function of operating frequency.

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AM EAS
Acousto Magnetic
Acousto systems Physical vibration in the
molecules of tag caused by RF pulses of 50.9 Hz
(19.6 ms) carried by 58 KHz signal. When the
transmitter pulse ends, the tag responds,
emitting a single frequency signal like a tuning
fork. Bias Magnet Reduces tags response from
frequency 2F to F. Magnetostrictive tag Physical
strain experienced in a material subjected to a
polarizing magnetic flux, or reversibly,
experiencing magnetic property changes to
external mechanical stresses.
Sensormatic
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EM EAS
Electro Magnetic

• Fundamental frequency 70 Hz to 1 KHz.
• Tags generate harmonics due to abrupt change in
  its magnetic state.
• Receiver detects fundamental, harmonics, and
  timing to activate an alarm.

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Swept RF EAS

• Transmitter produces signals between 7.4 to 8.8
  MHz.
• Tag is LC tuned network.
• Receiver detects phase difference between
  transmitted and tag signals.

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Microwave EAS

• 2 transmitters, hi and low frequencies.
• Hi frequency A) North America 902 to 906 MHz
  make 50 hoped frequencies, and B) Europe 1 fixed
  frequency between 2402 and 2486 MHz.
• Low frequency 111.5 KHz.
• Tag is tuned circuit that will radiate the sum
  and difference of hi and low frequencies.
• Receiver detects the modulated hi frequency
  signal.

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MUX Receiver Block Diagram
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Receiver
PGA
MUX
BPF
ADDER
GAIN
GAIN
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Challenges

• Real Time Locating System (RTLS). If expensive
  item is moved outside the surveillance area
  closest exit is locked, alarm sounds, items
  located by 3 positioning antennas and the backend
  software performs a triangular calculation and
  displays the location of the asset.
• Proximity detectors (switch, IR, or RF) for
  stand by mode.
• Compliance, future and backward compatibility,
  and networkability.
• Tags used to enter restricted areas for added
  security against merchandise loss.
• Buried pedestal antennas for wider entrances and
  better feeling for some.
• Improved packaging and silicon-ink imprinted
  tags.
• System work with any tag, tags work with any
  system, and -.
• Automatic VISA payment, automatic and customer
  self deactivation.
• If payment is made and tag sounds the alarm,
  customer can go back through pedestals, rescan to
  verify purchase, deactivate.
• System works if customer leaves but not enters.

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Q A
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Thank you for your participation.
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By Engr. Firas Faham