An 863–870 MHz spread-spectrum FSK transceiver design for wireless sensor

Abstract

Simulation results of a 863–870MHz frequency-hopped spread-spectrum (FHSS) transceiver with binary frequency shift keying (BFSK) modulation at 20kb/s for wireless sensor applications is presented.The transmit/receive RF front end contains a BFSK modulator, an upconversion mixer, a power amplifier (PA), and an 863–870MHz band pass filter (BPF) at the transmitter side and a low-noise amplifier with down conversion mixer to zero-IF, a low-pass channel-select filter, a limiter and a BFSK demodulator at the receiver side. The various block parameters of the transmit/receive RF front end like noise figure (NF), gain, 1dB compression point (P-1dB), and IIP3 are simulated and optimized to meet low power and low cost transceiver specifications.The transmitter simulations show an output ACPR (adjacent channel power ratio) of −22dBc, 3.3dBm P-1dB of PA, and transmitted power of 0dBm. The receiver simulations show 51.1dB conversion gain, −7dBm IIP3, −15dB return loss (S11), and 10dB NF. Low power arctangent-differentiated BFSK demodulator has been chosen and the BER performance has been co simulated with the analog receiver. The complete receiver achieves a BER of 10−3 at 10.5dB of EbtoNo. The transceiver simulations show an RMS frequency error of 1.45kHz.