In this paper, a wireless transceiver for digital communications in the ISM band(2400~2483.5MHz) is simulated, designed and implemented. The single up-conversion transmitter and the signal down-conversion receiver are used. Since the single up-conversion transmitter uses a high IF frequency(881.5MHz), the direct up-conversion transmitter is easily introduced and integrated.
This system uses a wideband DS-CDMA/TDD method with 4.3008Mcps chip rates, QPSK modulation and demodulation. This article focuses on QPSK digital modulation, a modulation scheme commonly used in full-service networks. This article also identifies typical RF-related impairments encountered when using this modulation technique. Impairments may occur in any combination within the time, frequency and amplitude domains. As the magnitude of impairments increases, the likelihood of incorrect mapping of signals after demodulation also increases the ultimate goal is to understand how impairments will impact bit error rates(BER) and is to gain error-free signal response across the entire system.
The design of a linear phase Nyquist filter is introduced. It is a very powerful, yet simple and straightforward design method. These all are simulated by the EEsof simulator.
