tailieunhanh - An Experimental Approach to CDMA and Interference Mitigation phần 10

Địa điểm và lộ trình giai đoạn: • f loor lập kế hoạch và vị trí vĩ mô • điện năng định tuyến • tế bào vị trí và định tuyến toàn cầu • đồng hồ cây sy nthesis • f iller tế bào • f inal định tuyến • các thông số khai thác Blast Fusi về | 246 Chapter 6 the power spectrum of the I component at the output of the CMF. The spectral image is located at fd - 4Rc MHz and the out of band noise power reduction performed by the digital front end as a whole is apparent if we compare this spectrum with the one in Figure 6-18. Time domain signals can be displayed either via a digital scope connected to the plug in DAC board or via the virtual scope provided by the BoxView tool. In this context Figure 6-23 sketches the I interpolator output when the non-orthogonal pilot is the only active channel1. Figure 6-23. Interpolator output signal useful channel plus pilot with P C 30 dB. Figure 6-24. AGC gain acquisition transient. Figure 6-24 shows the acquisition transient of the AGC gain signal as displayed on the visualization tool of the BoxView DSP software. The signal is read at symbol time by means of the DSP interface and the DSP stores its value in the data memory so as it can be read by the Master PC for visualization. The observation window time amounts at about to 250 symbol inter- 1 As the generation software did not allow the transmission without the reference channel we emulated the pilot only condition by setting P C 30 dB. 6. Testing and Verification of the MUSIC CDMA Receiver 247 vals. The agreement with previously produced bit true simulation results is excellent. Figure 6-25 displays the contents of the internal accumulator of the pilotchannel correlator in the SAC unit when Rb - 32 kbit s Rc -1024 kchip s L - 64 and no noise is affecting the transmission. The resulting waveform is a periodic ramp the pilot channel is unmodulated whose period equals the pilot code repetition length . the symbol period interval Ts 1 Rs 61 ps. Figure 6-25. Internal status of the I pilot correlator of the digital AGC. Figure 6-26 shows the time evolution of signal fract_del generated by the CCTU and controlling the re-sampling epoch input to the linear interpolator unit. This signal updated at symbol time is a .