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GR2 Class 1 Receiver

General Description

It is mandatory to use Class 1 wireless receiver modules in applications where human life can ultimately depend upon the reliable operation of a wireless data link. Such applications include nurse call and dispersed alarms or wireless fire alarm systems.

The up-graded GR2 receiver module meets these requirements and is available on any frequency.

Fully shielded and measuring just 21 x 48mm, Class1 receivers provide a superior route to enhancing the performance of current and future wireless enabled devices.

GR2

Applications

  • Nurse call
  • Dispersed alarms
  • Fire alarms
  • Domestic and commercial security

Features

  • Miniature SIL package
  • Switchable data rate filter offers;
  • 2400 baud with 117dBm sensitivity
  • 9600 baud with 110dBm sensitivity
  • Fully shielded
  • Single supply 2.7 to 10volt operation
  • Analogue, Digital and true RSSI outputs
  • Common genesis footprint
  • Operation on any VHF/UHF band
  • Other channels available on request
  • High blocking immunity in miniature package
  • Channel spacing 25 KHz

Compatible Transmitter Modules

  • GT2 (VHF 10mW transmitter module)
  • GT2D (UHF 10mW transmitter module)
  • GT2HP (VHF 200mW tx module)
  • GT2HP-869.6125 (UHF 300mW tx module)

Absolute Maximum Ratings

Operating temperature: -10°C to +55°C
Storage temperature: -40°C to +100°C
Supply Voltage (pin 5) 10V
RF Input (pin 1) 10mW

Electrical Characteristics: Receiver (869 MHz versions at 25degC & 2400 baud)

- pin min. typ. max. units notes
DC LEVELS

Supply voltage

2.7		 - 10 V -
Supply current - - 37 39 mA -
Supply ripple - - - 10 mVP-P -
Leakage current with Rx in sleep mode - - - 1 uA -
RF

RF sensitivity		 - - -117 - dBm 1
IF Bandwidth - - +/-12 - KHz -
Initial frequency accuracy - - ±25 - Hz -
Max R.F. input - - 10 - dBm -
Blocking - - 84 - dB -
E.M.C.
Spurious responses up to 1GHz - - <60 - dB -
LO leakage, conducted - - <70 - dBm -
LO leakage, radiated - - <70 - dBm -
Image rejection - - 65 - dB -
Adjacent channel rejection -
70 - dB -
DYNAMIC TIMING
Power up to stable data (With RF signal present - - 25 30 mS -
Signal to stable data (With power supply already on) - - - 3.0 mS -
Power up to valid RSSI (with RF signal present) - - 3.5 4.5 mS -
Mark: space ratio - - 50 - % -
Bit rate - 100 - 9600 bps -
Notes
1) For 12dB SINAD measured on AF output with 2400 baud filter selected.

Connection Details


Figure 1: GR2 Receiver

Baud Rate Selection

The module is supplied set to 2400 baud. The 9600 baud data rate can be selected by soldering the 2 sets of solder blob pads on the reverse side of the pcb.

RF IN (pin 1)

50W RF input from antenna, connect using shortest possible route. This input is isolated from the internal circuit using the air gap of the front end SAW RF filter.

RF GND (pin 2)

RF ground connection, preferably connected to a solid ground plane.

Enable (pin 3)

Active high. A low on this pin disables the receiver.

RSSI / Carrier Detect (pin 4)

The Received Signal Strength Indicator provides a DC output voltage proportional to the RF input signal. The amplitude of the RSSI voltage increases with increasing RF signal strength. A simple transistor interface can yield a carrier detect logic output.

Gnd (pin 5)

Connect to power supply ground

VCC (pin 6)

+Ve supply pin. A 100nF decoupling cap as close as possible to this pin and ground is recommended.

AF (pin 7)

Audio frequency output 100mV p-p.(max 40uA source)

DATA OUT (pin 8)

CMOS compatible output. This may be used to drive external decoders. (Internal 10k pull up)

Application Information

Antenna Design

The design and positioning of the antenna is as crucial as the module performance itself in achieving a good wireless system range. The following will assist the designer in maximising system performance.

The antenna should be kept as far away from sources of electrical interference as physically possible. If necessary, additional power line decoupling capacitors should be placed close to the module.

The antenna ‘hot end’ should be kept clear of any objects, especially any metal as this can severely restrict the efficiency of the antenna to receive power. Any earth planes restricting the radiation path to the antenna will also have the same effect.

Best range is achieved with either a straight piece of wire, rod or PCB track @ ¼ wavelength (8.2cm @ 869MHz). Further range may be achieved if the ¼ wave antenna is placed perpendicular in the middle of a solid earth plane measuring at least 10cm radius. In this case, the antenna should be connected to the module via some 50 ohm characteristic impedance coax.

Figure 2: Antenna Configurations To Be Used With The Genesis receiver Module

Application Circuit

The application circuit shows how the GR1 Receiver can easily be integrated into a system to form a wireless link.

Figure 3: Genesis Receiver Application Circuit

Mechanical Dimensions

Figure 4: Genesis Receiver

Ordering Information

Part No Description
GR2-869.2125FMC1 869.2125 MHz receiver module
GR2-869.6125FMC1 869.6125 MHz receiver module
GR2-458.85FMC1 458.85 MHz receiver module
GR2-434.075 434.075 MHz receiver module
GR2-434.275 434.275 MHz receiver module
GR2-434.475 434.475 MHz receiver module

NB: Other frequencies are possible

Disclaimer

MK Consultants have a policy to continually improve the reliability and performance of their products. We therefore reserve the right to upgrade our products performance without notice.
Although the data contained herewith is believed to be accurate, however we do not assume any responsibility whatsoever for errors or omissions this document may contain.
In addition, we do not imply warranty or fitness for any particular application especially life support applications.