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DOS

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+--------+-------------------------+-------------------------+--------+--------+
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|00001a10| 20 28 48 7a 29 20 3f 20 | 22 29 3b 0a 58 09 73 63 | (Hz) ? |");.X.sc|
|00001a20| 61 6e 66 28 22 25 6c 66 | 22 2c 20 26 73 61 6d 70 |anf("%lf|", &samp|
|00001a30| 6c 65 29 3b 0a 58 09 73 | 61 6d 70 6c 65 20 3d 20 |le);.X.s|ample = |
|00001a40| 28 64 6f 75 62 6c 65 29 | 31 2e 30 20 2f 20 73 61 |(double)|1.0 / sa|
|00001a50| 6d 70 6c 65 3b 0a 58 0a | 58 09 74 69 6d 65 20 3d |mple;.X.|X.time =|
|00001a60| 20 28 64 6f 75 62 6c 65 | 29 30 2e 30 3b 0a 58 09 | (double|)0.0;.X.|
|00001a70| 66 6f 72 20 28 6c 6f 6f | 70 20 3d 20 30 3b 20 6c |for (loo|p = 0; l|
|00001a80| 6f 6f 70 20 3c 20 73 61 | 6d 70 6c 65 73 3b 20 6c |oop < sa|mples; l|
|00001a90| 6f 6f 70 2b 2b 29 20 20 | 7b 0a 58 09 09 72 65 61 |oop++)  |{.X..rea|
|00001aa0| 6c 5b 6c 6f 6f 70 5d 20 | 3d 20 20 73 69 6e 28 50 |l[loop] |=  sin(P|
|00001ab0| 49 32 20 2a 20 66 72 65 | 71 20 2a 20 74 69 6d 65 |I2 * fre|q * time|
|00001ac0| 29 3b 0a 58 09 09 69 6d | 61 67 5b 6c 6f 6f 70 5d |);.X..im|ag[loop]|
|00001ad0| 20 3d 20 2d 63 6f 73 28 | 50 49 32 20 2a 20 66 72 | = -cos(|PI2 * fr|
|00001ae0| 65 71 20 2a 20 74 69 6d | 65 29 3b 0a 58 09 09 74 |eq * tim|e);.X..t|
|00001af0| 69 6d 65 20 2b 3d 20 73 | 61 6d 70 6c 65 3b 0a 58 |ime += s|ample;.X|
|00001b00| 09 7d 0a 58 0a 58 09 66 | 77 72 69 74 65 28 72 65 |.}.X.X.f|write(re|
|00001b10| 61 6c 2c 20 73 69 7a 65 | 6f 66 28 64 6f 75 62 6c |al, size|of(doubl|
|00001b20| 65 29 2c 20 73 61 6d 70 | 6c 65 73 2c 20 66 70 29 |e), samp|les, fp)|
|00001b30| 3b 0a 58 09 66 77 72 69 | 74 65 28 69 6d 61 67 2c |;.X.fwri|te(imag,|
|00001b40| 20 73 69 7a 65 6f 66 28 | 64 6f 75 62 6c 65 29 2c | sizeof(|double),|
|00001b50| 20 73 61 6d 70 6c 65 73 | 2c 20 66 70 29 3b 0a 58 | samples|, fp);.X|
|00001b60| 0a 58 09 66 63 6c 6f 73 | 65 28 66 70 29 3b 0a 58 |.X.fclos|e(fp);.X|
|00001b70| 09 70 75 74 63 68 61 72 | 28 27 5c 6e 27 29 3b 0a |.putchar|('\n');.|
|00001b80| 58 7d 0a 58 0a 58 2f 2a | 20 45 4f 46 20 2a 2f 0a |X}.X.X/*| EOF */.|
|00001b90| 45 4e 44 5f 4f 46 5f 67 | 65 6e 2e 63 0a 69 66 20 |END_OF_g|en.c.if |
|00001ba0| 74 65 73 74 20 31 32 39 | 32 20 2d 6e 65 20 60 77 |test 129|2 -ne `w|
|00001bb0| 63 20 2d 63 20 3c 67 65 | 6e 2e 63 60 3b 20 74 68 |c -c <ge|n.c`; th|
|00001bc0| 65 6e 0a 20 20 20 20 65 | 63 68 6f 20 73 68 61 72 |en.    e|cho shar|
|00001bd0| 3a 20 5c 22 67 65 6e 2e | 63 5c 22 20 75 6e 70 61 |: \"gen.|c\" unpa|
|00001be0| 63 6b 65 64 20 77 69 74 | 68 20 77 72 6f 6e 67 20 |cked wit|h wrong |
|00001bf0| 73 69 7a 65 21 0a 66 69 | 0a 23 20 65 6e 64 20 6f |size!.fi|.# end o|
|00001c00| 66 20 6f 76 65 72 77 72 | 69 74 69 6e 67 20 63 68 |f overwr|iting ch|
|00001c10| 65 63 6b 0a 66 69 0a 69 | 66 20 74 65 73 74 20 2d |eck.fi.i|f test -|
|00001c20| 66 20 66 66 74 2e 63 20 | 2d 61 20 22 24 7b 31 7d |f fft.c |-a "${1}|
|00001c30| 22 20 21 3d 20 22 2d 63 | 22 20 3b 20 74 68 65 6e |" != "-c|" ; then|
|00001c40| 20 0a 20 20 65 63 68 6f | 20 73 68 61 72 3a 20 57 | .  echo| shar: W|
|00001c50| 69 6c 6c 20 6e 6f 74 20 | 6f 76 65 72 2d 77 72 69 |ill not |over-wri|
|00001c60| 74 65 20 65 78 69 73 74 | 69 6e 67 20 66 69 6c 65 |te exist|ing file|
|00001c70| 20 5c 22 66 66 74 2e 63 | 5c 22 0a 65 6c 73 65 0a | \"fft.c|\".else.|
|00001c80| 65 63 68 6f 20 73 68 61 | 72 3a 20 45 78 74 72 61 |echo sha|r: Extra|
|00001c90| 63 74 69 6e 67 20 5c 22 | 66 66 74 2e 63 5c 22 20 |cting \"|fft.c\" |
|00001ca0| 5c 28 34 32 30 33 20 63 | 68 61 72 61 63 74 65 72 |\(4203 c|haracter|
|00001cb0| 73 5c 29 0a 73 65 64 20 | 22 73 2f 5e 58 2f 2f 22 |s\).sed |"s/^X//"|
|00001cc0| 20 3e 66 66 74 2e 63 20 | 3c 3c 27 45 4e 44 5f 4f | >fft.c |<<'END_O|
|00001cd0| 46 5f 66 66 74 2e 63 27 | 0a 58 2f 2a 0a 58 20 2a |F_fft.c'|.X/*.X *|
|00001ce0| 09 66 66 74 2e 63 0a 58 | 20 2a 0a 58 20 2a 09 43 |.fft.c.X| *.X *.C|
|00001cf0| 20 56 65 72 73 69 6f 6e | 20 31 2e 30 20 62 79 20 | Version| 1.0 by |
|00001d00| 53 74 65 76 65 20 53 61 | 6d 70 73 6f 6e 2c 20 50 |Steve Sa|mpson, P|
|00001d10| 75 62 6c 69 63 20 44 6f | 6d 61 69 6e 0a 58 20 2a |ublic Do|main.X *|
|00001d20| 0a 58 20 2a 09 54 68 69 | 73 20 70 72 6f 67 72 61 |.X *.Thi|s progra|
|00001d30| 6d 20 69 73 20 62 61 73 | 65 64 20 6f 6e 20 74 68 |m is bas|ed on th|
|00001d40| 65 20 77 6f 72 6b 20 62 | 79 20 57 2e 20 44 2e 20 |e work b|y W. D. |
|00001d50| 53 74 61 6e 6c 65 79 0a | 58 20 2a 09 61 6e 64 20 |Stanley.|X *.and |
|00001d60| 53 2e 20 4a 2e 20 50 65 | 74 65 72 73 6f 6e 2c 20 |S. J. Pe|terson, |
|00001d70| 4f 6c 64 20 44 6f 6d 69 | 6e 69 6f 6e 20 55 6e 69 |Old Domi|nion Uni|
|00001d80| 76 65 72 73 69 74 79 2e | 0a 58 20 2a 0a 58 20 2a |versity.|.X *.X *|
|00001d90| 09 54 68 69 73 20 70 72 | 6f 67 72 61 6d 20 70 72 |.This pr|ogram pr|
|00001da0| 6f 64 75 63 65 73 20 61 | 20 46 72 65 71 75 65 6e |oduces a| Frequen|
|00001db0| 63 79 20 44 6f 6d 61 69 | 6e 20 64 69 73 70 6c 61 |cy Domai|n displa|
|00001dc0| 79 0a 58 20 2a 09 66 72 | 6f 6d 20 74 68 65 20 54 |y.X *.fr|om the T|
|00001dd0| 69 6d 65 20 44 6f 6d 61 | 69 6e 20 64 61 74 61 20 |ime Doma|in data |
|00001de0| 69 6e 70 75 74 20 75 73 | 69 6e 67 20 74 68 65 20 |input us|ing the |
|00001df0| 46 61 73 74 20 46 6f 75 | 72 69 65 72 20 54 72 61 |Fast Fou|rier Tra|
|00001e00| 6e 73 66 6f 72 6d 2e 0a | 58 20 2a 0a 58 20 2a 09 |nsform..|X *.X *.|
|00001e10| 54 68 65 20 52 45 41 4c | 20 64 61 74 61 20 69 73 |The REAL| data is|
|00001e20| 20 67 65 6e 65 72 61 74 | 65 64 20 62 79 20 74 68 | generat|ed by th|
|00001e30| 65 20 69 6e 2d 70 68 61 | 73 65 20 28 49 29 20 63 |e in-pha|se (I) c|
|00001e40| 68 61 6e 6e 65 6c 20 61 | 6e 64 20 74 68 65 0a 58 |hannel a|nd the.X|
|00001e50| 20 2a 09 49 4d 41 47 49 | 4e 41 52 59 20 64 61 74 | *.IMAGI|NARY dat|
|00001e60| 61 20 69 73 20 70 72 6f | 64 75 63 65 64 20 62 79 |a is pro|duced by|
|00001e70| 20 74 68 65 20 71 75 61 | 64 72 61 74 75 72 65 2d | the qua|drature-|
|00001e80| 70 68 61 73 65 20 28 51 | 29 20 63 68 61 6e 6e 65 |phase (Q|) channe|
|00001e90| 6c 20 6f 66 0a 58 20 2a | 09 61 20 44 6f 70 70 6c |l of.X *|.a Doppl|
|00001ea0| 65 72 20 52 61 64 61 72 | 20 72 65 63 65 69 76 65 |er Radar| receive|
|00001eb0| 72 2e 20 20 54 68 65 20 | 6d 69 64 64 6c 65 20 66 |r.  The |middle f|
|00001ec0| 69 6c 74 65 72 20 69 73 | 20 7a 65 72 6f 20 48 7a |ilter is| zero Hz|
|00001ed0| 2e 20 20 43 6c 6f 73 69 | 6e 67 0a 58 20 2a 09 74 |.  Closi|ng.X *.t|
|00001ee0| 61 72 67 65 74 73 20 61 | 72 65 20 64 69 73 70 6c |argets a|re displ|
|00001ef0| 61 79 65 64 20 74 6f 20 | 74 68 65 20 72 69 67 68 |ayed to |the righ|
|00001f00| 74 2c 20 61 6e 64 20 4f | 70 65 6e 69 6e 67 20 74 |t, and O|pening t|
|00001f10| 61 72 67 65 74 73 20 74 | 6f 20 74 68 65 20 6c 65 |argets t|o the le|
|00001f20| 66 74 2e 0a 58 20 2a 0a | 58 20 2a 09 4e 6f 74 65 |ft..X *.|X *.Note|
|00001f30| 3a 20 57 69 74 68 20 49 | 4d 41 47 49 4e 41 52 59 |: With I|MAGINARY|
|00001f40| 20 64 61 74 61 20 73 65 | 74 20 74 6f 20 7a 65 72 | data se|t to zer|
|00001f50| 6f 20 74 68 65 20 6f 75 | 74 70 75 74 20 69 73 20 |o the ou|tput is |
|00001f60| 61 20 6d 69 72 72 6f 72 | 20 69 6d 61 67 65 2e 0a |a mirror| image..|
|00001f70| 58 20 2a 0a 58 20 2a 09 | 55 73 61 67 65 3a 09 66 |X *.X *.|Usage:.f|
|00001f80| 66 74 20 20 73 61 6d 70 | 6c 65 73 20 20 69 6e 70 |ft  samp|les  inp|
|00001f90| 75 74 5f 64 61 74 61 20 | 20 6f 75 74 70 75 74 5f |ut_data | output_|
|00001fa0| 64 61 74 61 0a 58 20 2a | 09 57 68 65 72 65 20 27 |data.X *|.Where '|
|00001fb0| 73 61 6d 70 6c 65 73 27 | 20 69 73 20 61 20 70 6f |samples'| is a po|
|00001fc0| 77 65 72 20 6f 66 20 74 | 77 6f 0a 58 20 2a 0a 58 |wer of t|wo.X *.X|
|00001fd0| 20 2a 09 41 72 72 61 79 | 20 56 65 72 73 69 6f 6e | *.Array| Version|
|00001fe0| 20 66 6f 72 20 54 75 72 | 62 6f 20 43 20 31 2e 35 | for Tur|bo C 1.5|
|00001ff0| 0a 58 20 2a 2f 0a 58 0a | 58 2f 2a 20 49 6e 63 6c |.X */.X.|X/* Incl|
|00002000| 75 64 65 73 20 2a 2f 0a | 58 0a 58 23 69 6e 63 6c |udes */.|X.X#incl|
|00002010| 75 64 65 20 3c 73 74 64 | 6c 69 62 2e 68 3e 0a 58 |ude <std|lib.h>.X|
|00002020| 23 69 6e 63 6c 75 64 65 | 20 3c 73 74 64 69 6f 2e |#include| <stdio.|
|00002030| 68 3e 0a 58 23 69 6e 63 | 6c 75 64 65 20 3c 6d 61 |h>.X#inc|lude <ma|
|00002040| 74 68 2e 68 3e 0a 58 23 | 69 6e 63 6c 75 64 65 20 |th.h>.X#|include |
|00002050| 3c 61 6c 6c 6f 63 2e 68 | 3e 0a 58 0a 58 2f 2a 20 |<alloc.h|>.X.X/* |
|00002060| 44 65 66 69 6e 65 73 20 | 2a 2f 0a 58 0a 58 23 64 |Defines |*/.X.X#d|
|00002070| 65 66 69 6e 65 09 54 57 | 4f 5f 50 49 09 28 28 64 |efine.TW|O_PI.((d|
|00002080| 6f 75 62 6c 65 29 32 2e | 30 20 2a 20 4d 5f 50 49 |ouble)2.|0 * M_PI|
|00002090| 29 0a 58 0a 58 2f 2a 20 | 47 6c 6f 62 61 6c 73 20 |).X.X/* |Globals |
|000020a0| 2a 2f 0a 58 0a 58 69 6e | 74 09 73 61 6d 70 6c 65 |*/.X.Xin|t.sample|
|000020b0| 73 2c 20 70 6f 77 65 72 | 3b 0a 58 64 6f 75 62 6c |s, power|;.Xdoubl|
|000020c0| 65 09 2a 72 65 61 6c 2c | 20 2a 69 6d 61 67 2c 20 |e.*real,| *imag, |
|000020d0| 6d 61 78 3b 0a 58 46 49 | 4c 45 09 2a 66 70 69 2c |max;.XFI|LE.*fpi,|
|000020e0| 20 2a 66 70 6f 3b 0a 58 | 0a 58 2f 2a 20 50 72 6f | *fpo;.X|.X/* Pro|
|000020f0| 74 6f 74 79 70 65 73 20 | 61 6e 64 20 66 6f 72 77 |totypes |and forw|
|00002100| 61 72 64 20 64 65 63 6c | 61 72 61 74 69 6f 6e 73 |ard decl|arations|
|00002110| 20 2a 2f 0a 58 0a 58 76 | 6f 69 64 09 66 66 74 28 | */.X.Xv|oid.fft(|
|00002120| 76 6f 69 64 29 2c 20 6d | 61 78 5f 61 6d 70 28 76 |void), m|ax_amp(v|
|00002130| 6f 69 64 29 2c 20 64 69 | 73 70 6c 61 79 28 76 6f |oid), di|splay(vo|
|00002140| 69 64 29 3b 0a 58 69 6e | 74 09 70 65 72 6d 75 74 |id);.Xin|t.permut|
|00002150| 65 28 69 6e 74 29 3b 0a | 58 64 6f 75 62 6c 65 09 |e(int);.|Xdouble.|
|00002160| 6d 61 67 6e 69 74 75 64 | 65 28 69 6e 74 29 3b 0a |magnitud|e(int);.|
|00002170| 58 0a 58 2f 2a 20 54 68 | 65 20 70 72 6f 67 72 61 |X.X/* Th|e progra|
|00002180| 6d 20 2a 2f 0a 58 0a 58 | 6d 61 69 6e 28 61 72 67 |m */.X.X|main(arg|
|00002190| 63 2c 20 61 72 67 76 29 | 0a 58 69 6e 74 09 61 72 |c, argv)|.Xint.ar|
|000021a0| 67 63 3b 0a 58 63 68 61 | 72 09 2a 61 72 67 76 5b |gc;.Xcha|r.*argv[|
|000021b0| 5d 3b 0a 58 7b 0a 58 09 | 69 6e 74 09 6e 3b 0a 58 |];.X{.X.|int.n;.X|
|000021c0| 0a 58 09 69 66 20 28 61 | 72 67 63 20 21 3d 20 34 |.X.if (a|rgc != 4|
|000021d0| 29 20 20 7b 0a 58 65 72 | 72 31 3a 09 09 66 70 72 |)  {.Xer|r1:..fpr|
|000021e0| 69 6e 74 66 28 73 74 64 | 65 72 72 2c 20 22 55 73 |intf(std|err, "Us|
|000021f0| 61 67 65 3a 20 66 66 74 | 20 73 61 6d 70 6c 65 73 |age: fft| samples|
|00002200| 20 69 6e 70 75 74 20 6f | 75 74 70 75 74 5c 6e 22 | input o|utput\n"|
|00002210| 29 3b 0a 58 09 09 66 70 | 72 69 6e 74 66 28 73 74 |);.X..fp|rintf(st|
|00002220| 64 65 72 72 2c 20 22 57 | 68 65 72 65 20 73 61 6d |derr, "W|here sam|
|00002230| 70 6c 65 73 20 69 73 20 | 61 20 70 6f 77 65 72 20 |ples is |a power |
|00002240| 6f 66 20 32 5c 6e 22 29 | 3b 0a 58 09 09 65 78 69 |of 2\n")|;.X..exi|
|00002250| 74 28 31 29 3b 0a 58 09 | 7d 0a 58 0a 58 09 73 61 |t(1);.X.|}.X.X.sa|
|00002260| 6d 70 6c 65 73 20 3d 20 | 61 62 73 28 61 74 6f 69 |mples = |abs(atoi|
|00002270| 28 61 72 67 76 5b 31 5d | 29 29 3b 0a 58 09 70 6f |(argv[1]|));.X.po|
|00002280| 77 65 72 20 3d 20 20 6c | 6f 67 31 30 28 28 64 6f |wer =  l|og10((do|
|00002290| 75 62 6c 65 29 73 61 6d | 70 6c 65 73 29 20 2f 20 |uble)sam|ples) / |
|000022a0| 6c 6f 67 31 30 28 28 64 | 6f 75 62 6c 65 29 32 2e |log10((d|ouble)2.|
|000022b0| 30 29 3b 0a 58 0a 58 09 | 69 66 20 28 28 72 65 61 |0);.X.X.|if ((rea|
|000022c0| 6c 20 3d 20 28 64 6f 75 | 62 6c 65 20 2a 29 6d 61 |l = (dou|ble *)ma|
|000022d0| 6c 6c 6f 63 28 73 61 6d | 70 6c 65 73 20 2a 20 73 |lloc(sam|ples * s|
|000022e0| 69 7a 65 6f 66 28 64 6f | 75 62 6c 65 29 29 29 20 |izeof(do|uble))) |
|000022f0| 3d 3d 20 4e 55 4c 4c 29 | 0a 58 65 72 72 32 3a 09 |== NULL)|.Xerr2:.|
|00002300| 09 66 70 72 69 6e 74 66 | 28 73 74 64 65 72 72 2c |.fprintf|(stderr,|
|00002310| 20 22 4f 75 74 20 6f 66 | 20 6d 65 6d 6f 72 79 5c | "Out of| memory\|
|00002320| 6e 22 29 3b 0a 58 0a 58 | 09 69 66 20 28 28 69 6d |n");.X.X|.if ((im|
|00002330| 61 67 20 3d 20 28 64 6f | 75 62 6c 65 20 2a 29 6d |ag = (do|uble *)m|
|00002340| 61 6c 6c 6f 63 28 73 61 | 6d 70 6c 65 73 20 2a 20 |alloc(sa|mples * |
|00002350| 73 69 7a 65 6f 66 28 64 | 6f 75 62 6c 65 29 29 29 |sizeof(d|ouble)))|
|00002360| 20 3d 3d 20 4e 55 4c 4c | 29 0a 58 09 09 67 6f 74 | == NULL|).X..got|
|00002370| 6f 20 65 72 72 32 3b 0a | 58 0a 58 09 69 66 20 28 |o err2;.|X.X.if (|
|00002380| 28 66 70 6f 20 3d 20 66 | 6f 70 65 6e 28 61 72 67 |(fpo = f|open(arg|
|00002390| 76 5b 33 5d 2c 20 22 77 | 62 22 29 29 20 3d 3d 20 |v[3], "w|b")) == |
|000023a0| 28 46 49 4c 45 20 2a 29 | 4e 55 4c 4c 29 0a 58 09 |(FILE *)|NULL).X.|
|000023b0| 09 67 6f 74 6f 20 65 72 | 72 31 3b 0a 58 0a 58 09 |.goto er|r1;.X.X.|
|000023c0| 69 66 20 28 28 66 70 69 | 20 3d 20 66 6f 70 65 6e |if ((fpi| = fopen|
|000023d0| 28 61 72 67 76 5b 32 5d | 2c 20 22 72 62 22 29 29 |(argv[2]|, "rb"))|
|000023e0| 20 21 3d 20 28 46 49 4c | 45 20 2a 29 4e 55 4c 4c | != (FIL|E *)NULL|
|000023f0| 29 20 20 7b 0a 58 09 09 | 66 72 65 61 64 28 72 65 |)  {.X..|fread(re|
|00002400| 61 6c 2c 20 73 69 7a 65 | 6f 66 28 64 6f 75 62 6c |al, size|of(doubl|
|00002410| 65 29 2c 20 73 61 6d 70 | 6c 65 73 2c 20 66 70 69 |e), samp|les, fpi|
|00002420| 29 3b 0a 58 09 09 66 72 | 65 61 64 28 69 6d 61 67 |);.X..fr|ead(imag|
|00002430| 2c 20 73 69 7a 65 6f 66 | 28 64 6f 75 62 6c 65 29 |, sizeof|(double)|
|00002440| 2c 20 73 61 6d 70 6c 65 | 73 2c 20 66 70 69 29 3b |, sample|s, fpi);|
|00002450| 0a 58 09 09 66 63 6c 6f | 73 65 28 66 70 69 29 3b |.X..fclo|se(fpi);|
|00002460| 0a 58 09 7d 0a 58 09 65 | 6c 73 65 0a 58 09 09 67 |.X.}.X.e|lse.X..g|
|00002470| 6f 74 6f 20 65 72 72 31 | 3b 0a 58 0a 58 09 66 66 |oto err1|;.X.X.ff|
|00002480| 74 28 29 3b 0a 58 09 6d | 61 78 5f 61 6d 70 28 29 |t();.X.m|ax_amp()|
|00002490| 3b 0a 58 09 64 69 73 70 | 6c 61 79 28 29 3b 0a 58 |;.X.disp|lay();.X|
|000024a0| 0a 58 09 66 77 72 69 74 | 65 28 72 65 61 6c 2c 20 |.X.fwrit|e(real, |
|000024b0| 73 69 7a 65 6f 66 28 64 | 6f 75 62 6c 65 29 2c 20 |sizeof(d|ouble), |
|000024c0| 73 61 6d 70 6c 65 73 2c | 20 66 70 6f 29 3b 0a 58 |samples,| fpo);.X|
|000024d0| 09 66 77 72 69 74 65 28 | 69 6d 61 67 2c 20 73 69 |.fwrite(|imag, si|
|000024e0| 7a 65 6f 66 28 64 6f 75 | 62 6c 65 29 2c 20 73 61 |zeof(dou|ble), sa|
|000024f0| 6d 70 6c 65 73 2c 20 66 | 70 6f 29 3b 0a 58 0a 58 |mples, f|po);.X.X|
|00002500| 09 66 63 6c 6f 73 65 28 | 66 70 6f 29 3b 0a 58 7d |.fclose(|fpo);.X}|
|00002510| 0a 58 0a 58 0a 58 76 6f | 69 64 20 66 66 74 28 29 |.X.X.Xvo|id fft()|
|00002520| 0a 58 7b 0a 58 09 75 6e | 73 69 67 6e 65 64 20 69 |.X{.X.un|signed i|
|00002530| 31 2c 20 69 32 2c 20 69 | 33 2c 20 69 34 2c 20 79 |1, i2, i|3, i4, y|
|00002540| 3b 0a 58 09 69 6e 74 09 | 20 6c 6f 6f 70 2c 20 6c |;.X.int.| loop, l|
|00002550| 6f 6f 70 31 2c 20 6c 6f | 6f 70 32 3b 0a 58 09 64 |oop1, lo|op2;.X.d|
|00002560| 6f 75 62 6c 65 09 20 61 | 31 2c 20 61 32 2c 20 62 |ouble. a|1, a2, b|
|00002570| 31 2c 20 62 32 2c 20 7a | 31 2c 20 7a 32 2c 20 76 |1, b2, z|1, z2, v|
|00002580| 3b 0a 58 0a 58 09 2f 2a | 20 53 63 61 6c 65 20 74 |;.X.X./*| Scale t|
|00002590| 68 65 20 64 61 74 61 20 | 2a 2f 0a 58 0a 58 09 66 |he data |*/.X.X.f|
|000025a0| 6f 72 20 28 6c 6f 6f 70 | 20 3d 20 30 3b 20 6c 6f |or (loop| = 0; lo|
|000025b0| 6f 70 20 3c 20 73 61 6d | 70 6c 65 73 3b 20 6c 6f |op < sam|ples; lo|
|000025c0| 6f 70 2b 2b 29 20 20 7b | 0a 58 09 09 72 65 61 6c |op++)  {|.X..real|
|000025d0| 5b 6c 6f 6f 70 5d 20 2f | 3d 20 28 64 6f 75 62 6c |[loop] /|= (doubl|
|000025e0| 65 29 73 61 6d 70 6c 65 | 73 3b 0a 58 09 09 69 6d |e)sample|s;.X..im|
|000025f0| 61 67 5b 6c 6f 6f 70 5d | 20 2f 3d 20 28 64 6f 75 |ag[loop]| /= (dou|
|00002600| 62 6c 65 29 73 61 6d 70 | 6c 65 73 3b 0a 58 09 7d |ble)samp|les;.X.}|
|00002610| 0a 58 0a 58 09 69 31 20 | 3d 20 73 61 6d 70 6c 65 |.X.X.i1 |= sample|
|00002620| 73 20 3e 3e 20 31 3b 0a | 58 09 69 32 20 3d 20 31 |s >> 1;.|X.i2 = 1|
|00002630| 3b 0a 58 09 76 20 3d 20 | 54 57 4f 5f 50 49 20 2a |;.X.v = |TWO_PI *|
|00002640| 20 28 28 64 6f 75 62 6c | 65 29 31 2e 30 20 2f 20 | ((doubl|e)1.0 / |
|00002650| 28 64 6f 75 62 6c 65 29 | 73 61 6d 70 6c 65 73 29 |(double)|samples)|
|00002660| 3b 0a 58 0a 58 09 66 6f | 72 20 28 6c 6f 6f 70 20 |;.X.X.fo|r (loop |
|00002670| 3d 20 30 3b 20 6c 6f 6f | 70 20 3c 20 70 6f 77 65 |= 0; loo|p < powe|
|00002680| 72 3b 20 6c 6f 6f 70 2b | 2b 29 20 20 7b 0a 58 09 |r; loop+|+)  {.X.|
|00002690| 09 69 33 20 3d 20 30 3b | 0a 58 09 09 69 34 20 3d |.i3 = 0;|.X..i4 =|
|000026a0| 20 69 31 3b 0a 58 0a 58 | 09 09 66 6f 72 20 28 6c | i1;.X.X|..for (l|
|000026b0| 6f 6f 70 31 20 3d 20 30 | 3b 20 6c 6f 6f 70 31 20 |oop1 = 0|; loop1 |
|000026c0| 3c 20 69 32 3b 20 6c 6f | 6f 70 31 2b 2b 29 20 20 |< i2; lo|op1++)  |
|000026d0| 7b 0a 58 09 09 09 79 20 | 3d 20 70 65 72 6d 75 74 |{.X...y |= permut|
|000026e0| 65 28 69 33 20 2f 20 69 | 31 29 3b 0a 58 09 09 09 |e(i3 / i|1);.X...|
|000026f0| 7a 31 20 3d 20 20 63 6f | 73 28 76 20 2a 20 79 29 |z1 =  co|s(v * y)|
|00002700| 3b 0a 58 09 09 09 7a 32 | 20 3d 20 2d 73 69 6e 28 |;.X...z2| = -sin(|
|00002710| 76 20 2a 20 79 29 3b 0a | 58 0a 58 09 09 09 66 6f |v * y);.|X.X...fo|
|00002720| 72 20 28 6c 6f 6f 70 32 | 20 3d 20 69 33 3b 20 6c |r (loop2| = i3; l|
|00002730| 6f 6f 70 32 20 3c 20 69 | 34 3b 20 6c 6f 6f 70 32 |oop2 < i|4; loop2|
|00002740| 2b 2b 29 20 20 7b 0a 58 | 09 09 09 09 61 31 20 3d |++)  {.X|....a1 =|
|00002750| 20 72 65 61 6c 5b 6c 6f | 6f 70 32 5d 3b 0a 58 09 | real[lo|op2];.X.|
|00002760| 09 09 09 61 32 20 3d 20 | 69 6d 61 67 5b 6c 6f 6f |...a2 = |imag[loo|
|00002770| 70 32 5d 3b 0a 58 0a 58 | 09 09 09 09 62 31 20 3d |p2];.X.X|....b1 =|
|00002780| 20 7a 31 2a 72 65 61 6c | 5b 6c 6f 6f 70 32 2b 69 | z1*real|[loop2+i|
|00002790| 31 5d 20 2d 20 7a 32 2a | 69 6d 61 67 5b 6c 6f 6f |1] - z2*|imag[loo|
|000027a0| 70 32 2b 69 31 5d 3b 0a | 58 09 09 09 09 62 32 20 |p2+i1];.|X....b2 |
|000027b0| 3d 20 7a 32 2a 72 65 61 | 6c 5b 6c 6f 6f 70 32 2b |= z2*rea|l[loop2+|
|000027c0| 69 31 5d 20 2b 20 7a 31 | 2a 69 6d 61 67 5b 6c 6f |i1] + z1|*imag[lo|
|000027d0| 6f 70 32 2b 69 31 5d 3b | 0a 58 0a 58 09 09 09 09 |op2+i1];|.X.X....|
|000027e0| 72 65 61 6c 5b 6c 6f 6f | 70 32 5d 20 20 20 20 20 |real[loo|p2]     |
|000027f0| 20 3d 20 61 31 20 2b 20 | 62 31 3b 0a 58 09 09 09 | = a1 + |b1;.X...|
|00002800| 09 69 6d 61 67 5b 6c 6f | 6f 70 32 5d 20 20 20 20 |.imag[lo|op2]    |
|00002810| 20 20 3d 20 61 32 20 2b | 20 62 32 3b 0a 58 0a 58 |  = a2 +| b2;.X.X|
|00002820| 09 09 09 09 72 65 61 6c | 5b 6c 6f 6f 70 32 20 2b |....real|[loop2 +|
|00002830| 20 69 31 5d 20 3d 20 61 | 31 20 2d 20 62 31 3b 0a | i1] = a|1 - b1;.|
|00002840| 58 09 09 09 09 69 6d 61 | 67 5b 6c 6f 6f 70 32 20 |X....ima|g[loop2 |
|00002850| 2b 20 69 31 5d 20 3d 20 | 61 32 20 2d 20 62 32 3b |+ i1] = |a2 - b2;|
|00002860| 0a 58 09 09 09 7d 0a 58 | 0a 58 09 09 09 69 33 20 |.X...}.X|.X...i3 |
|00002870| 2b 3d 20 28 69 31 20 3c | 3c 20 31 29 3b 0a 58 09 |+= (i1 <|< 1);.X.|
|00002880| 09 09 69 34 20 2b 3d 20 | 28 69 31 20 3c 3c 20 31 |..i4 += |(i1 << 1|
|00002890| 29 3b 0a 58 09 09 7d 0a | 58 0a 58 09 09 69 31 20 |);.X..}.|X.X..i1 |
|000028a0| 3e 3e 3d 20 31 3b 0a 58 | 09 09 69 32 20 3c 3c 3d |>>= 1;.X|..i2 <<=|
|000028b0| 20 31 3b 0a 58 09 7d 0a | 58 7d 0a 58 0a 58 2f 2a | 1;.X.}.|X}.X.X/*|
|000028c0| 0a 58 20 2a 09 46 69 6e | 64 20 6d 61 78 69 6d 75 |.X *.Fin|d maximu|
|000028d0| 6d 20 61 6d 70 6c 69 74 | 75 64 65 0a 58 20 2a 2f |m amplit|ude.X */|
|000028e0| 0a 58 0a 58 76 6f 69 64 | 20 6d 61 78 5f 61 6d 70 |.X.Xvoid| max_amp|
|000028f0| 28 29 0a 58 7b 0a 58 09 | 64 6f 75 62 6c 65 09 6d |().X{.X.|double.m|
|00002900| 61 67 3b 0a 58 09 69 6e | 74 09 6c 6f 6f 70 3b 0a |ag;.X.in|t.loop;.|
|00002910| 58 0a 58 09 6d 61 78 20 | 3d 20 28 64 6f 75 62 6c |X.X.max |= (doubl|
|00002920| 65 29 30 2e 30 3b 0a 58 | 09 66 6f 72 20 28 6c 6f |e)0.0;.X|.for (lo|
|00002930| 6f 70 20 3d 20 30 3b 20 | 6c 6f 6f 70 20 3c 20 73 |op = 0; |loop < s|
|00002940| 61 6d 70 6c 65 73 3b 20 | 6c 6f 6f 70 2b 2b 29 20 |amples; |loop++) |
|00002950| 20 7b 0a 58 09 09 69 66 | 20 28 28 6d 61 67 20 3d | {.X..if| ((mag =|
|00002960| 20 6d 61 67 6e 69 74 75 | 64 65 28 6c 6f 6f 70 29 | magnitu|de(loop)|
|00002970| 29 20 3e 20 6d 61 78 29 | 0a 58 09 09 09 6d 61 78 |) > max)|.X...max|
|00002980| 20 3d 20 6d 61 67 3b 0a | 58 09 7d 0a 58 7d 0a 58 | = mag;.|X.}.X}.X|
|00002990| 0a 58 2f 2a 0a 58 20 2a | 09 44 69 73 70 6c 61 79 |.X/*.X *|.Display|
|000029a0| 20 74 68 65 20 66 72 65 | 71 75 65 6e 63 79 20 64 | the fre|quency d|
|000029b0| 6f 6d 61 69 6e 2e 0a 58 | 20 2a 09 54 68 65 20 66 |omain..X| *.The f|
|000029c0| 69 6c 74 65 72 73 20 61 | 72 65 20 61 72 61 6e 67 |ilters a|re arang|
|000029d0| 65 64 20 73 6f 20 74 68 | 61 74 20 44 43 20 69 73 |ed so th|at DC is|
|000029e0| 20 69 6e 20 74 68 65 20 | 6d 69 64 64 6c 65 20 66 | in the |middle f|
|000029f0| 69 6c 74 65 72 2e 0a 58 | 20 2a 09 54 68 75 73 20 |ilter..X| *.Thus |
|00002a00| 2d 44 6f 70 70 6c 65 72 | 20 69 73 20 6f 6e 20 74 |-Doppler| is on t|
|00002a10| 68 65 20 6c 65 66 74 2c | 20 2b 44 6f 70 70 6c 65 |he left,| +Dopple|
|00002a20| 72 20 6f 6e 20 74 68 65 | 20 72 69 67 68 74 2e 0a |r on the| right..|
|00002a30| 58 20 2a 2f 0a 58 0a 58 | 76 6f 69 64 20 64 69 73 |X */.X.X|void dis|
|00002a40| 70 6c 61 79 28 29 0a 58 | 7b 0a 58 09 69 6e 74 09 |play().X|{.X.int.|
|00002a50| 63 2c 20 6e 2c 20 78 2c | 20 6c 6f 6f 70 3b 0a 58 |c, n, x,| loop;.X|
|00002a60| 0a 58 09 6e 20 3d 20 73 | 61 6d 70 6c 65 73 20 2f |.X.n = s|amples /|
|00002a70| 20 32 3b 0a 58 09 0a 58 | 09 66 6f 72 20 28 6c 6f | 2;.X..X|.for (lo|
|00002a80| 6f 70 20 3d 20 6e 3b 20 | 6c 6f 6f 70 20 3c 20 73 |op = n; |loop < s|
|00002a90| 61 6d 70 6c 65 73 3b 20 | 6c 6f 6f 70 2b 2b 29 20 |amples; |loop++) |
|00002aa0| 20 7b 0a 58 09 09 78 20 | 3d 20 28 69 6e 74 29 28 | {.X..x |= (int)(|
|00002ab0| 6d 61 67 6e 69 74 75 64 | 65 28 6c 6f 6f 70 29 20 |magnitud|e(loop) |
|00002ac0| 2a 20 28 64 6f 75 62 6c | 65 29 35 36 2e 30 20 2f |* (doubl|e)56.0 /|
|00002ad0| 20 6d 61 78 29 3b 0a 58 | 09 09 70 72 69 6e 74 66 | max);.X|..printf|
|00002ae0| 28 22 25 64 5c 74 7c 22 | 2c 20 6c 6f 6f 70 20 2d |("%d\t|"|, loop -|
|00002af0| 20 6e 29 3b 0a 58 09 09 | 63 20 3d 20 30 3b 0a 58 | n);.X..|c = 0;.X|
|00002b00| 09 09 77 68 69 6c 65 20 | 28 2b 2b 63 20 3c 3d 20 |..while |(++c <= |
|00002b10| 78 29 0a 58 09 09 09 70 | 75 74 63 68 61 72 28 27 |x).X...p|utchar('|
|00002b20| 3d 27 29 3b 0a 58 0a 58 | 09 09 70 75 74 63 68 61 |=');.X.X|..putcha|
|00002b30| 72 28 27 5c 6e 27 29 3b | 0a 58 09 7d 0a 58 0a 58 |r('\n');|.X.}.X.X|
|00002b40| 09 66 6f 72 20 28 6c 6f | 6f 70 20 3d 20 30 3b 20 |.for (lo|op = 0; |
|00002b50| 6c 6f 6f 70 20 3c 20 6e | 3b 20 6c 6f 6f 70 2b 2b |loop < n|; loop++|
|00002b60| 29 20 20 7b 0a 58 09 09 | 78 20 3d 20 28 69 6e 74 |)  {.X..|x = (int|
|00002b70| 29 28 6d 61 67 6e 69 74 | 75 64 65 28 6c 6f 6f 70 |)(magnit|ude(loop|
|00002b80| 29 20 2a 20 28 64 6f 75 | 62 6c 65 29 35 36 2e 30 |) * (dou|ble)56.0|
|00002b90| 20 2f 20 6d 61 78 29 3b | 0a 58 09 09 70 72 69 6e | / max);|.X..prin|
|00002ba0| 74 66 28 22 25 64 5c 74 | 7c 22 2c 20 6c 6f 6f 70 |tf("%d\t||", loop|
|00002bb0| 20 2b 20 6e 29 3b 0a 58 | 09 09 63 20 3d 20 30 3b | + n);.X|..c = 0;|
|00002bc0| 0a 58 09 09 77 68 69 6c | 65 20 28 2b 2b 63 20 3c |.X..whil|e (++c <|
|00002bd0| 3d 20 78 29 0a 58 09 09 | 09 70 75 74 63 68 61 72 |= x).X..|.putchar|
|00002be0| 28 27 3d 27 29 3b 0a 58 | 0a 58 09 09 70 75 74 63 |('=');.X|.X..putc|
|00002bf0| 68 61 72 28 27 5c 6e 27 | 29 3b 0a 58 09 7d 0a 58 |har('\n'|);.X.}.X|
|00002c00| 7d 0a 58 0a 58 2f 2a 0a | 58 20 2a 09 43 61 6c 63 |}.X.X/*.|X *.Calc|
|00002c10| 75 6c 61 74 65 20 50 6f | 77 65 72 20 4d 61 67 6e |ulate Po|wer Magn|
|00002c20| 69 74 75 64 65 0a 58 20 | 2a 2f 0a 58 0a 58 64 6f |itude.X |*/.X.Xdo|
|00002c30| 75 62 6c 65 20 6d 61 67 | 6e 69 74 75 64 65 28 6e |uble mag|nitude(n|
|00002c40| 29 0a 58 69 6e 74 09 6e | 3b 0a 58 7b 0a 58 09 6e |).Xint.n|;.X{.X.n|
|00002c50| 20 3d 20 70 65 72 6d 75 | 74 65 28 6e 29 3b 0a 58 | = permu|te(n);.X|
|00002c60| 09 72 65 74 75 72 6e 20 | 28 73 71 72 74 28 72 65 |.return |(sqrt(re|
|00002c70| 61 6c 5b 6e 5d 20 2a 20 | 72 65 61 6c 5b 6e 5d 20 |al[n] * |real[n] |
|00002c80| 2b 20 69 6d 61 67 5b 6e | 5d 20 2a 20 69 6d 61 67 |+ imag[n|] * imag|
|00002c90| 5b 6e 5d 29 29 3b 0a 58 | 7d 0a 58 0a 58 2f 2a 0a |[n]));.X|}.X.X/*.|
|00002ca0| 58 20 2a 09 42 69 74 20 | 72 65 76 65 72 73 65 20 |X *.Bit |reverse |
|00002cb0| 74 68 65 20 6e 75 6d 62 | 65 72 0a 58 20 2a 0a 58 |the numb|er.X *.X|
|00002cc0| 20 2a 09 43 68 61 6e 67 | 65 20 31 31 31 30 30 30 | *.Chang|e 111000|
|00002cd0| 30 30 62 20 74 6f 20 30 | 30 30 30 30 31 31 31 62 |00b to 0|0000111b|
|00002ce0| 20 6f 72 20 76 69 63 65 | 2d 76 65 72 73 61 0a 58 | or vice|-versa.X|
|00002cf0| 20 2a 2f 0a 58 0a 58 69 | 6e 74 20 70 65 72 6d 75 | */.X.Xi|nt permu|
|00002d00| 74 65 28 69 6e 64 65 78 | 29 0a 58 69 6e 74 09 69 |te(index|).Xint.i|
|00002d10| 6e 64 65 78 3b 0a 58 7b | 0a 58 09 69 6e 74 09 6e |ndex;.X{|.X.int.n|
|00002d20| 31 2c 20 72 65 73 75 6c | 74 2c 20 6c 6f 6f 70 3b |1, resul|t, loop;|
|00002d30| 0a 58 0a 58 09 6e 31 20 | 3d 20 73 61 6d 70 6c 65 |.X.X.n1 |= sample|
|00002d40| 73 3b 0a 58 09 72 65 73 | 75 6c 74 20 3d 20 30 3b |s;.X.res|ult = 0;|
|00002d50| 0a 58 0a 58 09 66 6f 72 | 20 28 6c 6f 6f 70 20 3d |.X.X.for| (loop =|
|00002d60| 20 30 3b 20 6c 6f 6f 70 | 20 3c 20 70 6f 77 65 72 | 0; loop| < power|
|00002d70| 3b 20 6c 6f 6f 70 2b 2b | 29 20 20 7b 0a 58 09 09 |; loop++|)  {.X..|
|00002d80| 6e 31 20 3e 3e 3d 20 31 | 3b 09 09 09 2f 2a 20 6e |n1 >>= 1|;.../* n|
|00002d90| 31 20 2f 20 32 2e 30 20 | 2a 2f 0a 58 09 09 69 66 |1 / 2.0 |*/.X..if|
|00002da0| 20 28 69 6e 64 65 78 20 | 3c 20 6e 31 29 0a 58 09 | (index |< n1).X.|
|00002db0| 09 09 63 6f 6e 74 69 6e | 75 65 3b 0a 58 0a 58 09 |..contin|ue;.X.X.|
|00002dc0| 09 72 65 73 75 6c 74 20 | 2b 3d 20 28 69 6e 74 29 |.result |+= (int)|
|00002dd0| 20 70 6f 77 28 28 64 6f | 75 62 6c 65 29 32 2e 30 | pow((do|uble)2.0|
|00002de0| 2c 20 28 64 6f 75 62 6c | 65 29 6c 6f 6f 70 29 3b |, (doubl|e)loop);|
|00002df0| 0a 58 09 09 69 6e 64 65 | 78 20 2d 3d 20 6e 31 3b |.X..inde|x -= n1;|
|00002e00| 0a 58 09 7d 0a 58 0a 58 | 09 72 65 74 75 72 6e 20 |.X.}.X.X|.return |
|00002e10| 72 65 73 75 6c 74 3b 0a | 58 7d 0a 58 0a 58 2f 2a |result;.|X}.X.X/*|
|00002e20| 20 45 4f 46 20 2a 2f 0a | 45 4e 44 5f 4f 46 5f 66 | EOF */.|END_OF_f|
|00002e30| 66 74 2e 63 0a 69 66 20 | 74 65 73 74 20 34 32 30 |ft.c.if |test 420|
|00002e40| 33 20 2d 6e 65 20 60 77 | 63 20 2d 63 20 3c 66 66 |3 -ne `w|c -c <ff|
|00002e50| 74 2e 63 60 3b 20 74 68 | 65 6e 0a 20 20 20 20 65 |t.c`; th|en.    e|
|00002e60| 63 68 6f 20 73 68 61 72 | 3a 20 5c 22 66 66 74 2e |cho shar|: \"fft.|
|00002e70| 63 5c 22 20 75 6e 70 61 | 63 6b 65 64 20 77 69 74 |c\" unpa|cked wit|
|00002e80| 68 20 77 72 6f 6e 67 20 | 73 69 7a 65 21 0a 66 69 |h wrong |size!.fi|
|00002e90| 0a 23 20 65 6e 64 20 6f | 66 20 6f 76 65 72 77 72 |.# end o|f overwr|
|00002ea0| 69 74 69 6e 67 20 63 68 | 65 63 6b 0a 66 69 0a 65 |iting ch|eck.fi.e|
|00002eb0| 63 68 6f 20 73 68 61 72 | 3a 20 45 6e 64 20 6f 66 |cho shar|: End of|
|00002ec0| 20 73 68 65 6c 6c 20 61 | 72 63 68 69 76 65 2e 0a | shell a|rchive..|
|00002ed0| 65 78 69 74 20 30 0a    |                         |exit 0. |        |
+--------+-------------------------+-------------------------+--------+--------+