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Phase-Noise EQ2440 26/3-2014 Per Zetterberg. I&Q Modulator x x +

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Presentation on theme: "Phase-Noise EQ2440 26/3-2014 Per Zetterberg. I&Q Modulator x x +"— Presentation transcript:

1 Phase-Noise EQ2440 26/3-2014 Per Zetterberg

2 I&Q Modulator x x +

3 I&Q Demodulator LP x x BP LP

4 With phase-noise With noise or interference Can leak into desired signal, when LO1 is non-ideal. SDR: Flexibility in digital => lots of E(f)

5 Time-Domain Phase-noise Modulated signal (partially known, e.g. training ) Phase-noise spectrum: or Don’t be to sure of which is refered to....

6 PLL Ref Phase Detector Loop- filter VCO Out - Noises: VCO: 1,1/f,1/f^2,1/f^3 1/N : 1, 1/f Phase detector: 1, 1/f Ref input:

7 Model PLL Dynamics And Phase- Noise Performance Phase Detector Loop- filter VCO

8 Phase-Noise Spectrum ADF4360 (RFX1800)

9 OFDM Subcarrier information symbols e.g. QPSK={- 1,+1,-j,+1} Cyclic prefix typically 10% Symbol time without CP. Phase-noise cause inter-carrier interference.

10 add_phase_noise.m Matlab function from MATLAB central. Spectrum defined in a PSD diagram (dBc) is used as input. The assumption is used. => Spectrum of is equal to spectrum of. The real-valued noise is generated in the frequency-domain using FFT (Gaussian noise. Independent from bin to bin). My question: How accurate is this model ? My observation: Very neat function.

11 A Novel Model for Simulation of RF Oscillator Phase Noise Paper by Siamak Yousefi potential PhD student at KTH. Studies problem scetched below. Some exact mathematical treatment and some approxmiations. Models noise close to carrier better than Leeson. Output of integrator unstable (my observation). Thermal and flicker noise Integratorexp(j*a)

12 For project course. Use matlab function add_phase_noise.m. Provide three basic settings. Good, fair and bad. Present PLL with slides. Refer to ”Phase Locked Loops for High- Frequency Receivers and Transmitters Part 1-3” and ”Model PLL Dynamics and Phase-Noise Performance”.


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