Ds302_3

AUG 01

©

©2001 REG No 277 4001 England

Page 4

QM Receiver Module

QMR1 / QMR2

QMR2 Details

QMR2

1

2

3

4

5

6

7

Figure 3 QMR2 Receiver

Pin Description:

RF IN ( pin 1 )

50 ohm 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 )

Supply ground connection. Preferably connected

to a solid ground plane.

RSSI ( pin 3 )

This is a dc output voltage that is proportional to

the RF signal strength applied to pin 1.

GND ( pin 4 )

Connected to power supply ground.

Vcc ( pin 5 )

+Ve supply pin. Operation from a 5V supply able

to source 6mA at less than Vp-p ripple.

AF ( pin 6 )

Audio frequency output. Note Source current is

limited to 40 microA. In most applications a buffer

may be required to interface to this pin.

DATA OUT ( pin 7 )

CMOS compatible output. This may be used to

drive external decoders.

General Information

Phase

Lock

Loop

RF

AMP

Band Pass

Filter

IF

AMP

Low Pass

Filter

Detector

Antenna

Mixer

Figure 4: Receiver Block Diagram

The QMR2 receiver module is a FM single

conversion superhet receiver capable of handling

data rates of up to 10Kbits/s. With an on board

data buffer, phase locked loop and a high quality

front end RF stage, a –107dBm sensitivity is

achieved.

Utilising the latest phase locked loop receiver

technology with one of the compatible transmitter

modules will yield a highly efficient wireless link.

RSSI Values

RF Level (dBm) pin 3

RSSI (volts) pin 6

-110

1.16

-100

1.34

-90

1.59

-80

1.78

-70

1.81

-60

1.81

-50

2.17

-40

2.45

-30

2.52

-20

2.52

-10

2.52