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A Design and Implementation of Digital Ultra-Narrowband Walky-Talky Using Direct Conversion Method  

Chong Young-Jun (Radio Technology Group, ETRI)
Kang Min-Soo (Radio Technology Group, ETRI)
Yoo Sung-Jin (Radio Technology Group, ETRI)
Chung Tae-Jin (Radio Technology Group, ETRI)
Oh Seung-Hyeub (Dept. of Electronics Engineering, Chungnam National University)
Publication Information
The Journal of Korean Institute of Electromagnetic Engineering and Science / v.16, no.6, 2005 , pp. 603-614 More about this Journal
Abstract
In this paper, digital ultra-narrowband Walky-Talky using direct conversion method for CQPSK modulation scheme is implemented with satisfying the requirements of APCO P25. RF transceiver design and implementation scheme that minimize the influence of DC-offset and AC-coupling at ultra-narrowband is proposed. This scheme also minimizes the influence of nonlinear characteristic at power amplifier fir CQPSK modulation method. Test results of full system including DSP module and direct conversion RF transceiver show that FCC emission mask at 36.8 dBm PEP meets the standard requirements. The characteristic of receiver AGC by PWM control signal is linear at 40 dB dynamic range and voice communication at input power level of -116 dBm is successful. Also it is verified that the performance of BER versus frequency offset and versus SNR meets the standard requirements.
Keywords
APCO P25; CQPSK; Ultra-Narrowband Walky-Talky;
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  • Reference
1 Project 25 Statement of Requirements - New Technology Standards Project Digital Radio Technical Standards, Nov. 1999
2 U. Mengali, A. N. D' Andrea, Synchronization Techniques for Digital Receivers, Plenum Press, Chap. 3-Chap. 7, 1997
3 TIA/EIA-102. BAAA, 'Project 25 FDMA common air interface new technology standards project digital radio technical standards', May 1998
4 ITU-R M.2014 Document, 'Spectrum efficient digital land mobile systems for dispatch traffic (Question ITU-R 37/8)', 1998
5 TIA-102. CAAA-A, 'Digital C4FM/CQPSK transceiver measurement methods', Nov. 2002
6 M. Order, H. Myer, 'Digital filter and square riming recovery', IEEE Trans. on Communications, pp. 605-612, May 1998
7 M. Boloorian, J. P. McGeehan, 'Linearization of frequency-hopped transmitters using cartesian feedback', Proc. IEEE VTC, pp. 520-524, 1995
8 F. M. Gardner, 'A BPSK/QPSK timing-error detector for sampled receivers', IEEE Trans. on Communications, vol. COM-34, pp. 423-429, May 1986
9 Part 90, Title 47, Code of Federal Regulations (Private Land Mobile Services), Edition, FCC, Oct. 2001
10 L. E. Larson, RF and Microwave Circuit Design for Wireless Communications, Artech House, Chap. 4, 1996