orumin
October 08, 2016
310

# 第12回カーネル/VM探検隊

October 08, 2016

## Transcript

2. ### CAUTION ແઢ๣ड಺༰ͷୈࡾऀ΁ͷ࿙Ӯɼ઄༻͸೔ຊࠃ๏཯ɼి೾๏ୈ 59 ৚ɼୈ 109 ৚ʹΑΓܐࣄേ෇Ͱېࢭ͞Ε͍ͯ·͢ ແ໔ڐແઢہʹΑΔ (ಛఆͷແઢҎ֎ͷ) ૹ৴͸ి೾๏ୈ 4

৚ͷෆ๏ແ ઢہʹ͋ͨΓɼേͤΒΕ·͢ ͜͜Ͱ͍͏ແઢہͱ͸ϒϩʔυόϯυ์ૹͷϥδΦɼςϨϏͷૹ৴ࢪઃͩ ͚Ͱͳ͘ɼి೾๏ୈ 2 ৚ୈ 5 ߸Ͱఆٛ͞ΕΔʮແઢઃඋٴͼແઢઃඋͷ ૢ࡞Λߦ͏ऀͷ૯ମʯΛࢦ͠·͢ 2 / 18

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5. ### ಉௐճ࿏ ω0 = 1 √ LC , f0 = 1

2π √ LC ΠϯμΫλ͸ిྲྀͷมԽʹΑͬͯىిྗ͕ൃੜ ίϯσϯα͸ిѹͷมԽʹΑͬͯిՙ͕มԽ VL(t) = L diL dt , iC(t) = C dVC dt ฒྻճ࿏Ͱ͸ɼ֤ૉࢠʹ͔͔Δిѹ͸౳͍͠ VL = VC ిؾճ࿏Ͱ͸ɼશͯͷૉࢠʹྲྀΕΔిྲྀͷ࿨͕ྵʹͳ Δ iC + iL = 0 d2i(t) dt2 + 1 LC i(t) = 0 同調回路 5 / 18
6. ### ݕ೾ճ࿏ ৴߸͔ΒแབྷઢΛͱΓͩ͢ ߭ੴ΍μΠΦʔυ͕ϑΟϧλͱͳͬ ͍ͯΔ ࣮͸ḊͼͨΧϛιϦͷਕͱΤϯϐπ ͷਊͰ΋ΠέΔ ͍ΘΏΔ foxhole radioʢᆠߺϥ δΦʣ

import numpy as np from scipy.signal import hilbert t = np.linspace(0,1,2048) E0 = 1 fc = 20 phi_c = 0 fm = 2 m = 0.9 phi_m = 0 E = E0*np.cos(fc*2*np.pi*t + phi_c) x = m*np.sin(fm*2*np.pi*t + phi_m) E_m = E0*np.cos(fc*2*np.pi*t + phi_c) \ *(1 - (m/2)*(1-np.sin(fm*2*np.pi*t+phi_m) signal = hilbert(E_m) envelope = np.abs(signal) 6 / 18

8. ### ϥδΦࠓੲ ͖͞΄Ͳ·Ͱ͸ɼੲͷ࿩ ΞφϩάϥδΦͩͱ৭ʑ໘౗ ૿෯ͱ͔νϡʔχϯάͱ͔ग़ྗஈͷՃ޻ͱ͔ ΈΜͳେ޷͖ DSP ͱμΠϨΫτίϯόʔδϣϯड৴ εʔύʔϔςϩμΠϯͷ IF Λ

0Hz ʹͨ͠ߏ଄ 8 / 18

9 / 18
10. ### I/Q ৴߸ ೖྗͷ RF ʹɼہ෦ൃৼث͔Β 90 ౓ͦΕͧΕҐ૬͕ҟͳΔ΋ͷΛՃ͑Δ In-phase ৴߸ Quadrature-phase

৴߸ νϡʔφʔνοϓ͸ I/Q ৴߸ʢϕʔεόϯυ৴߸ʣΛಘΔ 10 / 18

11 / 18

14. ### ͱ͜Ζ͜ͷ USB υϯάϧͬͯ ͦ͏Ͱ͢ɼϫϯηά TV ड৴༻ ͳΜͱळ༿ݪͰ 500 ԁͰߪೖ Ξϯςφ͸ΞϚνϡΞແઢͷ

144/430 MHz ༻Ͱɼ3000 ԁ͙Β͍ SDRʢSoftware-difined Radioʣ 14 / 18

18. ### ·ͱΊ ੲ͸ϥδΦ޻࡞͕ిࢠ޻࡞ͷೖ໳ʹΑ͘࢖ΘΕ͍ͯͨ ϥδΦ͔ΒΈΜͳ͕཭Ε͍ͯͬͯٱ͍͠ SDR ͰϥδΦΛௌ͘ͷ΋ྑ͍ͷͰͳ͍͔ Raspberry Pi ʹࢗ͠ͱ͍ͯϑϥΠτϨʔμʔ࡞Δͱ͔΋؆୯ radiko ϞυΩΛՈʹ࡞Δͷ΋Մೳ

͍Ζ͍Ζ༡ΜͰΈΑ͏ʂ 18 / 18