© 2001868/915 MHz Radio Module

Generic Low Power DC-200 kbps radio

LOW POWER ARCHITECTURE

• 50% reduction in power consumption• Fivefold increase in data rate• DC balancing of data not required• PLL based superheterodyne architecture• Received Signal Strength Indicator (70 dB range)• Output power level control

REALISATION• Bench top prototypes successfully tested 3-5 m line of sight links with zero BER• TR868 prototype dimensions: 48 mm x 34 mm•Total unit cost: ~$40

MOTIVATION • Move to less crowded 868MHz (Europe) and 915MHz (US) bands• Battery efficiency • Radio interference issues Image rejection Frequency stability Bandwidth efficiency•“Listen before transmit” Awareness of radio activity Power level control• Data rate/coding overhead limitation

Former RadioModule

868 MHz Module

PowerConsumption

65 mW5V @ 13 mA

32.4 mW3.6 V@9 mA

Data Rate 40 kbps Any rate up to 200 kbpsEncoding for DCBalancing

Manchester or 4b6brequired

Not necessary

SIMULATION

• ADS Circuit Envelope simulations at system and component level

VCXO MODULATION

• Reference crystal oscillator modulation: DC-200 kbps data rate• Gaussian pulse shaping of FSK data 65 dB ACPR Transients greatly reduced

DEMOD

OSC

1/N

TXOSC

RXOSC

PHASEDET.

TUNE

PLL

RECEIVER

TRANSMITTER

DATA IN

DATA OUT

300kHz600kHz 500kHz 250kHz

(1) (2)

Frequency (MHz)

Power(dBm)