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Add Frequency Table

This commit is contained in:
Michaelangel007 2017-04-16 00:23:24 -07:00
parent a58401fe54
commit 014f27b0cd
3 changed files with 462 additions and 1 deletions
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7
Makefile
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all: test_mock
all: test_mock freq
.PHONY: test_mock
C_FLAGS=-Wall -Wextra
test_mock:
src2dsk test_mock.s
applewin.sh -d1 test_mock.dsk
freq: freq.c
g++ $(C_FLAGS) $< -o $@

115
README.md
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Play a single note on both the left and right channels A.
Source: 6502 Assembly
# Mockingboard Tone <-> Frequency Table
See `freq.c`
```
Note Frequency Tone reproduced Relative Error
A0 27.500 Hz -> $0914 ~ 27.504 Hz (0.016 %)
A0# 29.135 Hz -> $0891 ~ 29.147 Hz (0.042 %)
B0 30.868 Hz -> $0816 ~ 30.879 Hz (0.038 %)
C1 32.703 Hz -> $07A2 ~ 32.713 Hz (0.029 %)
C1# 34.648 Hz -> $0734 ~ 34.664 Hz (0.047 %)
D1 36.708 Hz -> $06CD ~ 36.715 Hz (0.018 %)
D1# 38.891 Hz -> $066B ~ 38.905 Hz (0.036 %)
E1 41.203 Hz -> $060F ~ 41.212 Hz (0.022 %)
F1 43.654 Hz -> $05B8 ~ 43.662 Hz (0.018 %)
F1# 46.249 Hz -> $0566 ~ 46.252 Hz (0.006 %)
G1 48.999 Hz -> $0518 ~ 49.019 Hz (0.039 %)
G1# 51.913 Hz -> $04CF ~ 51.926 Hz (0.024 %)
A1 55.000 Hz -> $048A ~ 55.009 Hz (0.016 %)
A1# 58.270 Hz -> $0448 ~ 58.322 Hz (0.088 %)
B1 61.735 Hz -> $040B ~ 61.759 Hz (0.038 %)
C2 65.406 Hz -> $03D1 ~ 65.425 Hz (0.029 %)
C2# 69.296 Hz -> $039A ~ 69.328 Hz (0.047 %)
D2 73.416 Hz -> $0366 ~ 73.472 Hz (0.076 %)
D2# 77.782 Hz -> $0335 ~ 77.857 Hz (0.097 %)
E2 82.407 Hz -> $0307 ~ 82.478 Hz (0.086 %)
F2 87.307 Hz -> $02DC ~ 87.323 Hz (0.018 %)
F2# 92.499 Hz -> $02B3 ~ 92.504 Hz (0.006 %)
G2 97.999 Hz -> $028C ~ 98.037 Hz (0.039 %)
G2# 103.826 Hz -> $0267 ~ 103.936 Hz (0.105 %)
A2 110.000 Hz -> $0245 ~ 110.018 Hz (0.016 %)
A2# 116.541 Hz -> $0224 ~ 116.643 Hz (0.088 %)
B2 123.471 Hz -> $0205 ~ 123.637 Hz (0.135 %)
C3 130.813 Hz -> $01E8 ~ 130.985 Hz (0.131 %)
C3# 138.591 Hz -> $01CD ~ 138.656 Hz (0.047 %)
D3 146.832 Hz -> $01B3 ~ 146.944 Hz (0.076 %)
D3# 155.563 Hz -> $019A ~ 155.904 Hz (0.219 %)
E3 164.814 Hz -> $0183 ~ 165.169 Hz (0.216 %)
F3 174.614 Hz -> $016E ~ 174.646 Hz (0.018 %)
F3# 184.997 Hz -> $0159 ~ 185.277 Hz (0.151 %)
G3 195.998 Hz -> $0146 ~ 196.075 Hz (0.039 %)
G3# 207.652 Hz -> $0133 ~ 208.210 Hz (0.269 %)
A3 220.000 Hz -> $0122 ~ 220.415 Hz (0.189 %)
A3# 233.082 Hz -> $0112 ~ 233.286 Hz (0.088 %)
B3 246.942 Hz -> $0102 ~ 247.754 Hz (0.329 %)
C4 261.626 Hz -> $00F4 ~ 261.969 Hz (0.131 %)
C4# 277.183 Hz -> $00E6 ~ 277.915 Hz (0.264 %)
D4 293.665 Hz -> $00D9 ~ 294.564 Hz (0.306 %)
D4# 311.127 Hz -> $00CD ~ 311.807 Hz (0.219 %)
E4 329.628 Hz -> $00C1 ~ 331.194 Hz (0.475 %)
F4 349.228 Hz -> $00B7 ~ 349.292 Hz (0.018 %)
F4# 369.994 Hz -> $00AC ~ 371.631 Hz (0.442 %)
G4 391.995 Hz -> $00A3 ~ 392.150 Hz (0.039 %)
G4# 415.305 Hz -> $0099 ~ 417.781 Hz (0.596 %)
A4 440.000 Hz -> $0091 ~ 440.831 Hz (0.189 %)
A4# 466.164 Hz -> $0089 ~ 466.573 Hz (0.088 %)
B4 493.883 Hz -> $0081 ~ 495.507 Hz (0.329 %)
C5 523.251 Hz -> $007A ~ 523.938 Hz (0.131 %)
C5# 554.365 Hz -> $0073 ~ 555.830 Hz (0.264 %)
D5 587.330 Hz -> $006C ~ 591.856 Hz (0.771 %)
D5# 622.254 Hz -> $0066 ~ 626.671 Hz (0.710 %)
E5 659.255 Hz -> $0060 ~ 665.838 Hz (0.999 %)
F5 698.456 Hz -> $005B ~ 702.422 Hz (0.568 %)
F5# 739.989 Hz -> $0056 ~ 743.261 Hz (0.442 %)
G5 783.991 Hz -> $0051 ~ 789.141 Hz (0.657 %)
G5# 830.609 Hz -> $004C ~ 841.059 Hz (1.258 %)
A5 880.000 Hz -> $0048 ~ 887.784 Hz (0.885 %)
A5# 932.328 Hz -> $0044 ~ 940.007 Hz (0.824 %)
B5 987.767 Hz -> $0040 ~ 998.757 Hz (1.113 %)
C6 1046.502 Hz -> $003D ~1047.876 Hz (0.131 %)
C6# 1108.731 Hz -> $0039 ~1121.411 Hz (1.144 %)
D6 1174.659 Hz -> $0036 ~1183.712 Hz (0.771 %)
D6# 1244.508 Hz -> $0033 ~1253.342 Hz (0.710 %)
E6 1318.510 Hz -> $0030 ~1331.676 Hz (0.999 %)
F6 1396.913 Hz -> $002D ~1420.454 Hz (1.685 %)
F6# 1479.978 Hz -> $002B ~1486.522 Hz (0.442 %)
G6 1567.982 Hz -> $0028 ~1598.011 Hz (1.915 %)
G6# 1661.219 Hz -> $0026 ~1682.117 Hz (1.258 %)
A6 1760.000 Hz -> $0024 ~1775.568 Hz (0.885 %)
A6# 1864.655 Hz -> $0022 ~1880.013 Hz (0.824 %)
B6 1975.533 Hz -> $0020 ~1997.514 Hz (1.113 %)
C7 2093.005 Hz -> $001E ~2130.682 Hz (1.800 %)
C7# 2217.461 Hz -> $001C ~2282.873 Hz (2.950 %)
D7 2349.318 Hz -> $001B ~2367.424 Hz (0.771 %)
D7# 2489.016 Hz -> $0019 ~2556.818 Hz (2.724 %)
E7 2637.020 Hz -> $0018 ~2663.352 Hz (0.999 %)
F7 2793.826 Hz -> $0016 ~2905.475 Hz (3.996 %)
F7# 2959.955 Hz -> $0015 ~3043.831 Hz (2.834 %)
G7 3135.963 Hz -> $0014 ~3196.022 Hz (1.915 %)
G7# 3322.438 Hz -> $0013 ~3364.234 Hz (1.258 %)
A7 3520.000 Hz -> $0012 ~3551.136 Hz (0.885 %)
A7# 3729.310 Hz -> $0011 ~3760.026 Hz (0.824 %)
B7 3951.066 Hz -> $0010 ~3995.028 Hz (1.113 %)
C8 4186.009 Hz -> $000F ~4261.363 Hz (1.800 %)
C8# 4434.922 Hz -> $000E ~4565.746 Hz (2.950 %)
D8 4698.636 Hz -> $000D ~4916.957 Hz (4.646 %)
D8# 4978.032 Hz -> $000C ~5326.704 Hz (7.004 %)
E8 5274.041 Hz -> $000C ~5326.704 Hz (0.999 %)
F8 5587.652 Hz -> $000B ~5810.950 Hz (3.996 %)
F8# 5919.911 Hz -> $000A ~6392.045 Hz (7.975 %)
G8 6271.927 Hz -> $000A ~6392.045 Hz (1.915 %)
G8# 6644.875 Hz -> $0009 ~7102.272 Hz (6.883 %)
```

341
freq.c Normal file
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/*
Frequency To/From Mockingboard Tones
by Michael Pohoreski
GitHub: https://github.com/Michaelangel007/apple2_mockingboard
The Mockingboard document at:
* ftp://ftp.apple.asimov.net/pub/apple_II/documentation/hardware/sound/Mockingboard%20Docs.pdf
has several incorrect values:
APPENDIX E
Course & Fine
Note Octave Frequency Decimal Hex. Notes
A 0 27.500 9 20 09 14 Exact 27.5 Hz -- bottom key on Piano
A# 0 29.135 8 145 08 91
B 0 30.868 8 22 08 16
C 1 32.703 7 163 07 A3 <-- should be 7A2
C# 1 34.648 7 53 07 35 <-- should be 734
D 1 36.708 6 205 06 CD
D# 1 38.891 6 108 06 6C <-- should be 66B
E 1 41.203 6 15 06 0F
F 1 43.654 5 184 05 B8
F# 1 46.249 5 102 05 66
G 1 48.999 5 24 05 18
G# 1 51.913 4 207 04 CF
A 1 55.000 4 138 04 8A Exact 55.0 Hz
A# 1 58.270 4 73 04 49 <-- should be 448
B 1 61.735 4 11 04 0B
C 2 65.406 3 209 03 D1
C# 2 69.296 3 154 03 9A
D 2 73.416 3 102 03 66
D# 2 77.782 3 54 03 36 <-- should be 335
E 2 82.406 3 7 03 07
F 2 87.308 2 220 02 DC
F# 2 92.498 2 179 02 B3
G 2 97.998 2 140 02 8C
G# 3 103.826 2 103 02 67
A 3 110.000 2 69 02 45 Exact 110.0 Hz
A# 3 116.540 2 36 02 24
B 3 123.470 2 5 02 05
C 3 130.812 1 232 01 E8
C# 3 138.592 1 205 01 CD
D 3 146.832 1 179 01 B3
D# 3 155.564 1 155 01 9B <-- should be 19A
E 3 164.812 1 131 01 83
F 3 174.616 1 110 01 6E
F# 3 184.996 1 89 01 59
G 3 195.996 1 70 01 46
G# 3 207.652 1 51 01 33
A 3 220.000 1 34 01 22
A# 3 233.080 1 18 01 12
B 3 246.940 1 2 01 02
C 4 261.624 0 244 00 F4 -- Middle C4 --
C# 4 277.184 0 230 00 E6
D 4 293.664 0 217 00 D9
D# 4 311.128 0 205 00 CD
E 4 329.624 0 193 00 C1 <-- 329.628 Hz
F 4 349.232 0 183 00 B7 <-- 349.228 Hz
F# 4 369.992 0 172 00 AC
G 4 391.992 0 163 00 A3
G# 4 415.304 0 153 00 99
A 4 440.000 0 145 00 91 Exact 440 Hz -- Concert Tuning A440
A# 4 466.160 0 137 00 89
B 4 493.880 0 129 00 81
C 5 523.248 0 122 00 7A
C# 5 554.368 0 115 00 73
D 5 587.328 0 108 00 6C
D# 5 622.256 0 102 00 66
E 5 659.248 0 96 00 60 <-- 659.255 Hz
F 5 698.464 0 91 00 58 <-- Should be 5B
F# 5 739.984 0 86 00 56
G 5 783.984 0 81 00 51
G# 5 830.608 0 76 00 4C
A 5 880.000 0 72 00 48 Exact 880 Hz
A# 5 932.320 0 68 00 44 <-- 932.328 Hz
B 5 987.760 0 64 00 40 <-- 987.767 Hz
C 6 1046.496 0 61 00 3D -- every frequency
C# 6 1108.736 0 57 00 39 -- from this point
D 6 1174.656 0 54 00 36 -- forward is slightly
D# 6 1244.512 0 51 00 33 -- off except for 'A'
E 6 1318.496 0 48 00 30
F 6 1396.928 0 45 00 2D <--1396.913 Hz
F# 6 1479.968 0 43 00 2B
G 6 1567.968 0 40 00 2B <-- Should be 28
G# 6 1661.216 0 38 00 26
A 6 1760.000 0 36 00 24 Exact 1760 Hz
A# 6 1864.640 0 34 00 22
B 6 1975.520 0 32 00 20
C 7 2092.992 0 30 00 1E <-- 2093.005 Hz
C# 7 2217.472 0 28 00 1C
D 7 2349.312 0 27 00 1B
D# 7 2489.024 0 25 00 19
E 7 2636.992 0 24 00 18
F 7 2793.856 0 22 00 16
F# 7 2959.936 0 21 00 15
G 7 3135.936 0 20 00 14
G# 7 3322.432 0 19 00 13
A 7 3520.000 0 18 00 12 Exact 3520 Hz
A# 7 3729.280 0 17 00 11
B 7 3951.040 0 16 00 10
C 8 4185.984 0 15 00 0F -- top key on Piano
C# 8 4434.944 0 14 00 0E
D 8 4698.624 0 13 00 0D
D# 8 4978.048 0 12 00 0C
E 8 5273.984 0 12 00 0C <-- 5274.041 Hz
F 8 5587.712 0 11 00 0B
F# 8 5919.872 0 10 00 0A
G 8 6271.872 0 10 00 0A
G# 8 6644.864 0 9 00 09
A 8 7040.000 0 9 00 09 Exact 7040 Hz
A# 8 7458.560 0 8 00 08
B 8 7902.080 0 8 00 08
And here are the correc frequencies and tones
along with the relative error:
Note Frequency Tone reproduced Relative Error
A0 27.500 Hz -> $0914 ~ 27.504 Hz (0.016 %)
A0# 29.135 Hz -> $0891 ~ 29.147 Hz (0.042 %)
B0 30.868 Hz -> $0816 ~ 30.879 Hz (0.038 %)
C1 32.703 Hz -> $07A2 ~ 32.713 Hz (0.029 %)
C1# 34.648 Hz -> $0734 ~ 34.664 Hz (0.047 %)
D1 36.708 Hz -> $06CD ~ 36.715 Hz (0.018 %)
D1# 38.891 Hz -> $066B ~ 38.905 Hz (0.036 %)
E1 41.203 Hz -> $060F ~ 41.212 Hz (0.022 %)
F1 43.654 Hz -> $05B8 ~ 43.662 Hz (0.018 %)
F1# 46.249 Hz -> $0566 ~ 46.252 Hz (0.006 %)
G1 48.999 Hz -> $0518 ~ 49.019 Hz (0.039 %)
G1# 51.913 Hz -> $04CF ~ 51.926 Hz (0.024 %)
A1 55.000 Hz -> $048A ~ 55.009 Hz (0.016 %)
A1# 58.270 Hz -> $0448 ~ 58.322 Hz (0.088 %)
B1 61.735 Hz -> $040B ~ 61.759 Hz (0.038 %)
C2 65.406 Hz -> $03D1 ~ 65.425 Hz (0.029 %)
C2# 69.296 Hz -> $039A ~ 69.328 Hz (0.047 %)
D2 73.416 Hz -> $0366 ~ 73.472 Hz (0.076 %)
D2# 77.782 Hz -> $0335 ~ 77.857 Hz (0.097 %)
E2 82.407 Hz -> $0307 ~ 82.478 Hz (0.086 %)
F2 87.307 Hz -> $02DC ~ 87.323 Hz (0.018 %)
F2# 92.499 Hz -> $02B3 ~ 92.504 Hz (0.006 %)
G2 97.999 Hz -> $028C ~ 98.037 Hz (0.039 %)
G2# 103.826 Hz -> $0267 ~ 103.936 Hz (0.105 %)
A2 110.000 Hz -> $0245 ~ 110.018 Hz (0.016 %)
A2# 116.541 Hz -> $0224 ~ 116.643 Hz (0.088 %)
B2 123.471 Hz -> $0205 ~ 123.637 Hz (0.135 %)
C3 130.813 Hz -> $01E8 ~ 130.985 Hz (0.131 %)
C3# 138.591 Hz -> $01CD ~ 138.656 Hz (0.047 %)
D3 146.832 Hz -> $01B3 ~ 146.944 Hz (0.076 %)
D3# 155.563 Hz -> $019A ~ 155.904 Hz (0.219 %)
E3 164.814 Hz -> $0183 ~ 165.169 Hz (0.216 %)
F3 174.614 Hz -> $016E ~ 174.646 Hz (0.018 %)
F3# 184.997 Hz -> $0159 ~ 185.277 Hz (0.151 %)
G3 195.998 Hz -> $0146 ~ 196.075 Hz (0.039 %)
G3# 207.652 Hz -> $0133 ~ 208.210 Hz (0.269 %)
A3 220.000 Hz -> $0122 ~ 220.415 Hz (0.189 %)
A3# 233.082 Hz -> $0112 ~ 233.286 Hz (0.088 %)
B3 246.942 Hz -> $0102 ~ 247.754 Hz (0.329 %)
C4 261.626 Hz -> $00F4 ~ 261.969 Hz (0.131 %)
C4# 277.183 Hz -> $00E6 ~ 277.915 Hz (0.264 %)
D4 293.665 Hz -> $00D9 ~ 294.564 Hz (0.306 %)
D4# 311.127 Hz -> $00CD ~ 311.807 Hz (0.219 %)
E4 329.628 Hz -> $00C1 ~ 331.194 Hz (0.475 %)
F4 349.228 Hz -> $00B7 ~ 349.292 Hz (0.018 %)
F4# 369.994 Hz -> $00AC ~ 371.631 Hz (0.442 %)
G4 391.995 Hz -> $00A3 ~ 392.150 Hz (0.039 %)
G4# 415.305 Hz -> $0099 ~ 417.781 Hz (0.596 %)
A4 440.000 Hz -> $0091 ~ 440.831 Hz (0.189 %)
A4# 466.164 Hz -> $0089 ~ 466.573 Hz (0.088 %)
B4 493.883 Hz -> $0081 ~ 495.507 Hz (0.329 %)
C5 523.251 Hz -> $007A ~ 523.938 Hz (0.131 %)
C5# 554.365 Hz -> $0073 ~ 555.830 Hz (0.264 %)
D5 587.330 Hz -> $006C ~ 591.856 Hz (0.771 %)
D5# 622.254 Hz -> $0066 ~ 626.671 Hz (0.710 %)
E5 659.255 Hz -> $0060 ~ 665.838 Hz (0.999 %)
F5 698.456 Hz -> $005B ~ 702.422 Hz (0.568 %)
F5# 739.989 Hz -> $0056 ~ 743.261 Hz (0.442 %)
G5 783.991 Hz -> $0051 ~ 789.141 Hz (0.657 %)
G5# 830.609 Hz -> $004C ~ 841.059 Hz (1.258 %)
A5 880.000 Hz -> $0048 ~ 887.784 Hz (0.885 %)
A5# 932.328 Hz -> $0044 ~ 940.007 Hz (0.824 %)
B5 987.767 Hz -> $0040 ~ 998.757 Hz (1.113 %)
C6 1046.502 Hz -> $003D ~1047.876 Hz (0.131 %)
C6# 1108.731 Hz -> $0039 ~1121.411 Hz (1.144 %)
D6 1174.659 Hz -> $0036 ~1183.712 Hz (0.771 %)
D6# 1244.508 Hz -> $0033 ~1253.342 Hz (0.710 %)
E6 1318.510 Hz -> $0030 ~1331.676 Hz (0.999 %)
F6 1396.913 Hz -> $002D ~1420.454 Hz (1.685 %)
F6# 1479.978 Hz -> $002B ~1486.522 Hz (0.442 %)
G6 1567.982 Hz -> $0028 ~1598.011 Hz (1.915 %)
G6# 1661.219 Hz -> $0026 ~1682.117 Hz (1.258 %)
A6 1760.000 Hz -> $0024 ~1775.568 Hz (0.885 %)
A6# 1864.655 Hz -> $0022 ~1880.013 Hz (0.824 %)
B6 1975.533 Hz -> $0020 ~1997.514 Hz (1.113 %)
C7 2093.005 Hz -> $001E ~2130.682 Hz (1.800 %)
C7# 2217.461 Hz -> $001C ~2282.873 Hz (2.950 %)
D7 2349.318 Hz -> $001B ~2367.424 Hz (0.771 %)
D7# 2489.016 Hz -> $0019 ~2556.818 Hz (2.724 %)
E7 2637.020 Hz -> $0018 ~2663.352 Hz (0.999 %)
F7 2793.826 Hz -> $0016 ~2905.475 Hz (3.996 %)
F7# 2959.955 Hz -> $0015 ~3043.831 Hz (2.834 %)
G7 3135.963 Hz -> $0014 ~3196.022 Hz (1.915 %)
G7# 3322.438 Hz -> $0013 ~3364.234 Hz (1.258 %)
A7 3520.000 Hz -> $0012 ~3551.136 Hz (0.885 %)
A7# 3729.310 Hz -> $0011 ~3760.026 Hz (0.824 %)
B7 3951.066 Hz -> $0010 ~3995.028 Hz (1.113 %)
C8 4186.009 Hz -> $000F ~4261.363 Hz (1.800 %)
C8# 4434.922 Hz -> $000E ~4565.746 Hz (2.950 %)
D8 4698.636 Hz -> $000D ~4916.957 Hz (4.646 %)
D8# 4978.032 Hz -> $000C ~5326.704 Hz (7.004 %)
E8 5274.041 Hz -> $000C ~5326.704 Hz (0.999 %)
F8 5587.652 Hz -> $000B ~5810.950 Hz (3.996 %)
F8# 5919.911 Hz -> $000A ~6392.045 Hz (7.975 %)
G8 6271.927 Hz -> $000A ~6392.045 Hz (1.915 %)
G8# 6644.875 Hz -> $0009 ~7102.272 Hz (6.883 %)
Reference:
* https://en.wikipedia.org/wiki/Piano_key_frequencies
* http://www.sciencebuddies.org/Fi les/3443/5/Phys_img024.jpg
*/
#include <stdio.h>
#include <math.h>
const double _1MHz_NTSC = 14318180.0 / 14.0; // 1,022,727 Hz
//const double _1MHz_PAL = 14250000.0 / 14.0;
//const double A2_FREQ = 1023000.0; // common incorrect value
/*
Mockingboard:
Tone Freq = A2 Clock Freq / ((256*Course + Fine) * 16)
6502:
Master = 14.31818 MHz
NTSC Cycle = 14.31818 / 14 = 1.0227271429... MHz = 1022727 Hz
PAL Cycle = 14.25 / 14 = 1.0178571429... MHz = 1017857 Hz
n = 1,022,727 / freq
Course = n / 4096
Fine = (n - (4069*Course)) / 16
*/
// Convert Frequency into Mockingboard Tone Period
// ========================================================================
int MockingboardGetTone( double freq_hz )
{
const int n = (int) (_1MHz_NTSC / freq_hz);
const int hi = n / 4096;
const int lo = (n - (hi * 4096)) / 16;
return (hi*256) + lo;
}
// Convert Mockingboard Tone Period into Frequency
// ========================================================================
double MockingboardGetFreq( int tone_period )
{
// / 256 = >> 8
// * 4096 = << 12
// int n = ((tone_period & 0xFF00) << 4) + ((tone_period & 0x00FF) << 4);
return _1MHz_NTSC / (double) (tone_period << 4);
}
// ========================================================================
int main()
{
const char *names[ 12 ] =
{
"A ", // 2^( 0/12)
"A#", // 2^( 1/12)
"B ", // 2^( 2/12)
"C ", // 2^( 3/12)
"C#", // 2^( 4/12)
"D ", // 2^( 5/12)
"D#", // 2^( 6/12)
"E ", // 2^( 7/12)
"F ", // 2^( 8/12)
"F#", // 2^( 9/12)
"G ", // 2^(10/12)
"G#" // 2^(11/12)
};
double halfstep_freq[12];
for( int half_step = 0; half_step < 12; half_step++ )
halfstep_freq[ half_step ] = pow( 2.0, (half_step / 12.0) );
for( int octave = 0; octave < 8; octave++ )
{
double octave_freq = 440.0 * pow( 2.0, (octave - 4.0));
for( int half_step = 0; half_step < 12; half_step++ )
{
double actual = octave_freq * halfstep_freq[ half_step ];
int tone = MockingboardGetTone( actual );
double measure = MockingboardGetFreq( tone );
double rel_err = (measure - actual) / actual * 100.0;
printf( "%c%d%c %8.3f Hz -> $%04X ~%8.3f Hz (%5.3f %%)\n"
, names[ half_step ][0]
, octave + (half_step > 2)
, names[ half_step ][1]
, actual
, tone
, measure
, rel_err
);
if( half_step == 2 )
printf( "\n" );
}
}
printf( "\n" );
return 0;
}