Overview What is Wireless? How Does it Work? Problems and Limitations Mounting Locations Paradox...

Overview

• What is Wireless?

• How Does it Work?

• Problems and Limitations

• Mounting Locations

• Paradox Wireless Technology

• Paradox Wireless Products

What is Wireless?

• A term used to describe telecommunications in which electromagnetic waves, rather than some form of wire, carry signals over the communication path

• Most wireless products use Radio Frequency (RF) signals to communicate

What is Wireless?

• RF waves occupy a large portion of the electromagnetic spectrum – from 9kHz to 300GHz

What is Wireless?

• The RF spectrum is divided into 8 bands• Paradox wireless products are in UHF band

Paradox Products

* Often referred to as the microwave spectrum.

10 mm – 1 mm30 GHz – 300 GHzEHFExtremely High Frequency*

100 mm – 10 mm3 GHz – 30 GHzSHFSuper High Frequency*

1 m – 100 mm300 MHz – 3 GHzUHFUltra High Frequency

10 m – 1 m30 MHz – 300 MHzVHFVery High Frequency

100 m – 10 m3 MHz – 30 MHzHFHigh Frequency

1 km – 100 m300 kHz – 3 MHzMFMedium Frequency

10 km – 1 km30 kHz – 300 kHzLFLow Frequency

33 km – 10 km9 kHz – 30 kHzVLFVery Low Frequency

Free-space WavelengthsFrequenciesAbbreviationDesignation

How Does it Work?

• A wireless system is made up of a receiver (Rx) and transmitters (Tx)

• When an RF current (AC) is supplied to an antenna, it generates an electromagnetic field (RF field) that is suitable for wireless broadcasting and/or communication

Example

• Example: A motion detector (Tx) has an open zone

– Detector (Tx) converts the digital signal (binary) into an RF signal

Example

Example

– The RF signal is sent from the detector to the receiver via the antenna

Example

– The receiver converts the RF signal back to a digital signal

Example

– The digital signal is then interpreted by either an outside source (i.e. control panel) or within the receiver itself (i.e. Magellan)

Problems and Limitations

• The main obstacle to wireless systems is interference, which can cause minor annoyances or prevent the system from functioning altogether

• Interference simplified:– Imagine you are in a room in front of 1000 people, who are all

talking at the same time, and you try to listen to only one person in the crowd. During this time, a police car goes by with its siren on and a dog is barking. Each person, the police siren and the dog represent different signals at different frequencies.

– The noisy people, police siren and barking dog are all sources of interference

Problems and Limitations

• Types of Interference– Radio Frequency (RF) Interference

• Multipath Interference

– Electrical Interference– Intermodulation

• RF Reflection and Attenuation

RF Interference

• RF Interference– Defined as an undesired signal received by a wireless

device that prevents it from receiving clear signal reception

– Any device that generates RF as part of its functionality can also cause RFI

– The interfering signal does not have to be on the same frequency. Signals that are near the receiver’s frequency can also interfere with the receiver

RF Interference

• Possible sources of RFI:– AM, short-wave, FM and TV broadcast transmitters– Ham radio and CB transmitters– Remote controls– Wireless phones– Cellular phones

RF Interference

– Commercial taxi, police and aircraft radios– Microwave ovens– Motion sensors– Radar systems– And many more medical and industrial devices

Multipath Interference

• Multipath Interference– A form of RF interference– Occurs when more than one RF wave from the same

transmitter reaches the receiver


– The RF signal moves between the transmitting and receiving antenna in the most direct path (A), but it also reflects (B) off metallic and other surfaces


– When the different RF waves combine they cause distortion to the desired RF wave, which makes the signal difficult to decode


– In extreme situations, the reflected RF wave (B) inverts and cancels out the direct path RF wave (A)


– To remedy this, simply move the transmitter or receiver a few inches

Electrical Interference

• Electrical Interference– Caused by the unintentional generation of RF due to

an electrical spark, arc or discharge– Any wiring connected to the spark source conducts

the RF and acts as a transmitting antenna– As a general rule, the noisier an electrical device is

the potential it has of generating RF noise


• Three types of electrical interference– RF noise from electrical equipment– RF noise generated by electronic devices– Interference from natural sources such as lightning


• Possible sources of electrical interference:– TV or computer cathode ray tube (CRT) displays– Electric welders– Air conditioners– Brush-type motors


– Relays and switches of all kinds– Arcing and corona discharge in power line insulators– Malfunctioning flourescent/neon lighting and

automobile spark plugs– Light dimmers

Intermodulation

• Intermodulation– Occurs when a strong signal (i.e. communications

tower), whose frequency is generally not near that of the wireless receiver, overloads some circuit in the receiver

– As a result, the circuit generates harmonics of the strong signal, which then combine in the receiver to create a new frequency

Intermodulation

– The newly created frequency, called an Intermodulation Product, interferes with the wireless system in much the same way as other sources of interference

– For example, mounting a transmitter too close to a receiver can cause intermodulation. The signal from the transmitter is too strong due to its proximity to the receiver

RF Reflection and Attenuation

• RF Reflection and Attenuation– Reflection: RF signals bounce off a reflective surface

such as a wall or the ground– Attenuation: When RF signals pass through solid

objects, some of the signal power is absorbed. This loss of RF energy is called Attenuation, which varies depending on the structure of the object


– An installation site’s physical construction and the obstacles on the site affect RF signals

– Walls, doors, floors, elevator shafts, people and other obstacles offer varying degrees of attenuation and reflection

– This causes the RF radiation pattern to be irregular and unpredictable


• When an RF wave meets an obstacle, one of the following three phenomena occur:– Reflection

• Reflection from walls, ceilings and floor surfaces can be partial or complete and cause multipath interference


– Refraction• Occurs when an RF wave crosses a boundary from one

medium to another (i.e. from air to water). A wave entering a medium at an angle will change direction


– Diffraction: It is the bending of RF waves around an object’s edge, such as a sharp corner or opening


• Objects that reflect and attenuate RF signals include:– Metal objects– Objects with metal in them– Ground– Circuit breaker boxes– Trees: RF energy loss depends on the size and type

of tree. Large trees with dense foliage create greater loss


– Walls: Interior walls create less RF energy loss and exterior walls, especially those with stucco, create greater loss

– Floors: Wood floors create less RF energy loss and concrete and steel floors create greater loss

– Mirrored walls have very high RF energy loss because the reflective coating is conductive

Mounting Locations

• Mounting locations affect the overall performance of the wireless system

• In order to ensure the best possible signal reception, the following list of criteria should be respected whenever possible

Mounting Locations

• Select an installation site that is free of obstacles that reflect and absorb RF signals (RF reflection and attenuation), and avoid installation near or in the path of strong RF fields (interference)– One of the most basic obstacles is the ground and its

relation to the receiver. The ground works as an RF noise generator, and also mirrors RF signals and sometimes even absorbs them

Mounting Locations

– Avoid mounting the receiver in the basement as the range of the receiver is reduced when mounted below ground level

– If it is absolutely necessary that the receiver be mounted in the basement, ensure that it is mounted as high and as close to the underside of the first floor as possible

Mounting Locations

• Select a site that is not susceptible to drastic temperature changes– Mounting the receiver or transmitter in an area with

drastic temperature changes can cause condensation and moisture to collect in the receiver or transmitter

– Common problem areas include:• Heater air duct• Exterior doors• Refrigerators and freezers• Garage

Mounting Locations

• Mount the wireless receiver as high and as central as possible to the proposed placement of the transmitters– Ideally, the perfect antenna spreads its signal like a

perfectly round circle. However, because of the transmitter’s physical construction (i.e. PCB, battery) it is more like a figure 8.

Mounting Locations

– The “dead spot”, or area where the RF signal is weak or non-existent, varies from one transmitter to the next

– Mounting the receiver as central as possible to the transmitters will help in avoiding the “dead spots”

Mounting Locations

• Do not mount the transmitters too close to each other. Do not mount the transmitters too far or too close to the receiver– When RF devices are too close, strong RF signals

can cause the devices to malfunction (Intermodulation)

– When a transmitter is mounted too far from the receiver, the RF signal is too weak to communicate effectively or at all

Mounting Locations

– As a general rule, when installing transmitters ensure that there is at least 30cm (1ft) between each transmitter, and at least 1.5m (5ft) between each transmitter and the receiver

– The maximum distance that a transmitter can be from the receiver is dependant on the transmitter’s transmission range

Paradox Wireless Technology

• Paradox wireless products– 433MHz and 868MHz– UHF band of the RF spectrum


• Reliable Data Transmission and Reception– Information is sent and received consistently and

without error– Cyclic Redundancy Check (CRC) Algorithm

• An error correction code that is used to catch errors in data• Verifies the integrity of the data to ensure that the signal

comes from the correct source

– Every message that is sent by a transmitter to the receiver is sent 8 times for increased reliability in noisy environments

• Only 1 of the 8 messages must be correct for the receiver to process the message


• Receiver Sensitivity– A receiver’s sensitivity is the ability to discriminate

between a good signal and the noise generated by the environment and the receiver circuit itself

– Low threshold for increased sensitivity• Can distinguish between the desired signal and noise that is

very close to the desired signal’s frequency

– A low-noise amplifier raises the power level of the received RF signal for increased sensitivity

– CRC algorithm checks for any errors in the data


– 4-Step Noise Filtering removes as much noise from the received signal as possible

• Surface Acoustic Wave (SAW) filter• Ceramic filter• Low-pass filter• Software filter


• Transmitters– Use a quartz crystal oscillator to stabilize the output

frequency and ensure that the signal frequency is always in the band of the receiver


• Antennas– Tuned specifically for 433MHz or 868MHz

• Antenna receives the strongest signals at 433MHz or 868MHz. Other signals at different frequencies are received but are weaker

– Receiver antenna tuned to receive the desired signal at its highest power level (1/4 wavelength)


– Spectra 1759MG• One 1/4-wavelength

ground plane monopole


– MG-RCV3• One 1/4-wavelength

monopole


– Magellan• 433MHz: One 1/4-wavelength

folded monopole

• 868Mhz: One helical

antenna


– Transmitters• One helical

• Except remotecontrols andMG-DCT2: One PCB-Printed

antenna


• Installation features– Save time when selecting mounting locations for the

receiver and transmitters– Signal Strength Test

• Used to verify the signal strength of each transmitter

– Noise Level Test• Used to verify the environment noise surrounding the

receiver

• Supervision features– Low-battery– Tamper– Check-in

Paradox Wireless Products

• Paradox wireless products are available in 433MHz and 868MHz


• Spectra 1759MG– 15-zone wireless control

panel– Built-in wireless

receiver


• Magellan (MG-6060)– Magellan all-in-one wireless console


• MG-RCV3– Magellan wireless

expansion module


• Transmitters– Motion Detectors

Wireless PIR Motion Detector with Built-in Pet Immunity (18kg/40lb Pet Immunity)

PMD2P

Digital Dual-Optic High Performance PIR

(40kg/90lbsTrue Pet Immunity)

MG-PMD75

Digital Dual-Optic High Performance Outdoor PIR (40kg/90lbs True Pet Immunity)

MG-PMD85


– Door Contacts

Long-Range Door Contact

MG-DCT1

Ultra-Small Door Contact

MG-DCT2

Door Contact

MG-DCTXP


– Remote Controls

Remote Control with Backlight Buttons

MG-REM1

2-Way Remote Control with Backlight Buttons

MG-REM2


– Remote Controls

Magellan Remote Control with Magellan Remote Control with Integrated Access CardIntegrated Access Card

MG-RAC1MG-RAC1


– Accessory

Smoke DetectorMade by EVERday (Taiwan)

SD738

Overview What is Wireless? How Does it Work? Problems and Limitations Mounting Locations Paradox...

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