# Signetics 2650 & 2636 programming/PVI audio frequency chart
## Frequency table

The chart below shows the audio frequency generated by the PVI when the value n is programmed into $1FC7.
| | period | cycles per frame | frequency | A4=440Hz | A4=440Hz | error | error |
| n | 128(n+1)μs | | Hz | note/octave | ideal f | diff, Hz | diff, % |
| 0 | OFF | | | | | | |
| 1 | 256 | 78.13 | 3906.25 | B7 | 3951.07 | 44.82 | 1.13 |
| 2 | 384 | 52.08 | 2604.17 | E7 | 2637.02 | 32.85 | 1.25 |
| 3 | 512 | 39.06 | 1953.13 | B6 | 1975.53 | 22.41 | 1.13 |
| 4 | 640 | 31.25 | 1562.50 | G6 | 1661.22 | 98.72 | 5.94 |
| 5 | 768 | 26.04 | 1302.08 | E6 | 1318.51 | 16.43 | 1.25 |
| 6 | 896 | 22.32 | 1116.07 | C♯6 | 1108.73 | -7.34 | -0.66 |
| 7 | 1024 | 19.53 | 976.56 | B5 | 987.77 | 11.21 | 1.13 |
| 8 | 1152 | 17.36 | 868.06 | A5 | 880.00 | 11.94 | 1.36 |
| 9 | 1280 | 15.63 | 781.25 | G5 | 783.99 | 2.74 | 0.35 |
| 10 | 1408 | 14.20 | 710.23 | F5 | 698.46 | -11.77 | -1.68 |
| 11 | 1536 | 13.02 | 651.04 | E5 | 659.25 | 8.21 | 1.25 |
| 12 | 1664 | 12.02 | 600.96 | D5 | 587.33 | -13.63 | -2.32 |
| 13 | 1792 | 11.16 | 558.04 | C♯5 | 554.37 | -3.67 | -0.66 |
| 14 | 1920 | 10.42 | 520.83 | C5 | 523.25 | 2.42 | 0.46 |
| 15 | 2048 | 9.77 | 488.28 | B4 | 493.88 | 5.60 | 1.13 |
| 16 | 2176 | 9.19 | 459.56 | A♯4 | 466.16 | 6.60 | 1.42 |
| 17 | 2304 | 8.68 | 434.03 | A4 | 440.00 | 5.97 | 1.36 |
| 18 | 2432 | 8.22 | 411.18 | G♯4 | 415.30 | 4.12 | 0.99 |
| 19 | 2560 | 7.81 | 390.63 | G4 | 392.00 | 1.37 | 0.35 |
| 20 | 2688 | 7.44 | 372.02 | F♯4 | 369.99 | -2.03 | -0.55 |
| 21 | 2816 | 7.10 | 355.11 | F4 | 349.23 | -5.88 | -1.68 |
| 22 | 2944 | 6.79 | 339.67 | | | | |
| 23 | 3072 | 6.51 | 325.52 | E4 | 329.63 | 4.11 | 1.25 |
| 24 | 3200 | 6.25 | 312.50 | D♯4 | 311.13 | -1.37 | -0.44 |
| 25 | 3328 | 6.01 | 300.48 | | | | |
| 26 | 3456 | 5.79 | 289.35 | D4 | 293.66 | 4.31 | 1.47 |
| 27 | 3584 | 5.58 | 279.02 | C♯4 | 277.18 | -1.84 | -0.66 |
| 28 | 3712 | 5.39 | 269.40 | | | | |
| 29 | 3840 | 5.21 | 260.42 | C4 | 261.63 | 1.21 | 0.46 |
| 30 | 3968 | 5.04 | 252.02 | | | | |
| 31 | 4096 | 4.88 | 244.14 | B3 | 246.94 | 2.80 | 1.13 |
| 32 | 4224 | 4.73 | 236.74 | | | | |
| 33 | 4352 | 4.60 | 229.78 | A♯3 | 233.08 | 3.30 | 1.42 |
| 34 | 4480 | 4.46 | 223.21 | | | | |
| 35 | 4608 | 4.34 | 217.01 | A3 | 220.00 | 2.99 | 1.36 |
| 36 | 4736 | 4.22 | 211.15 | | | | |
| 37 | 4864 | 4.11 | 205.59 | G♯3 | 207.65 | 2.06 | 0.99 |
| 38 | 4992 | 4.01 | 200.32 | | | | |
| 39 | 5120 | 3.91 | 195.31 | G3 | 196.00 | 0.69 | 0.35 |
| 40 | 5248 | 3.81 | 190.55 | | | | |
| 41 | 5376 | 3.72 | 186.01 | F♯3 | 185.00 | -1.01 | -0.55 |
| 42 | 5504 | 3.63 | 181.69 | | | | |
| 43 | 5632 | 3.55 | 177.56 | | | | |
| 44 | 5760 | 3.47 | 173.61 | F3 | 174.61 | 1.00 | 0.57 |
| 45 | 5888 | 3.40 | 169.84 | | | | |
| 46 | 6016 | 3.32 | 166.22 | E3 | 164.81 | -1.41 | -0.86 |
| 47 | 6144 | 3.26 | 162.76 | | | | |
| 48 | 6272 | 3.19 | 159.44 | | | | |
| 49 | 6400 | 3.13 | 156.25 | D♯3 | 155.56 | -0.69 | -0.44 |
| 50 | 6528 | 3.06 | 153.19 | | | | |
| 51 | 6656 | 3.00 | 150.24 | | | | |
| 52 | 6784 | 2.95 | 147.41 | D3 | 146.83 | -0.58 | -0.39 |
| 53 | 6912 | 2.89 | 144.68 | | | | |
| 54 | 7040 | 2.84 | 142.05 | | | | |
| 55 | 7168 | 2.79 | 139.51 | C♯3 | 138.59 | -0.92 | -0.66 |
| 56 | 7296 | 2.74 | 137.06 | | | | |
| 57 | 7424 | 2.69 | 134.70 | | | | |
| 58 | 7552 | 2.65 | 132.42 | | | | |
| 59 | 7680 | 2.60 | 130.21 | C3 | 130.81 | 0.60 | 0.46 |
| 60 | 7808 | 2.56 | 128.07 | | | | |
| 61 | 7936 | 2.52 | 126.01 | | | | |
| 62 | 8064 | 2.48 | 124.01 | | | | |
| 63 | 8192 | 2.44 | 122.07 | B2 | 123.47 | 1.40 | 1.13 |
| 64 | 8320 | 2.40 | 120.19 | | | | |
| 65 | 8448 | 2.37 | 118.37 | | | | |
| 66 | 8576 | 2.33 | 116.60 | A♯2 | 116.54 | -0.06 | -0.06 |
| 67 | 8704 | 2.30 | 114.89 | | | | |
| 68 | 8832 | 2.26 | 113.22 | | | | |
| 69 | 8960 | 2.23 | 111.61 | | | | |
| 70 | 9088 | 2.20 | 110.04 | A2 | 110.00 | -0.04 | -0.03 |
| 71 | 9216 | 2.17 | 108.51 | | | | |
| 72 | 9344 | 2.14 | 107.02 | | | | |
| 73 | 9472 | 2.11 | 105.57 | | | | |
| 74 | 9600 | 2.08 | 104.17 | G♯2 | 103.83 | -0.34 | -0.32 |
| 75 | 9728 | 2.06 | 102.80 | | | | |
| 76 | 9856 | 2.03 | 101.46 | | | | |
| 77 | 9984 | 2.00 | 100.16 | | | | |
| 78 | 10112 | 1.98 | 98.89 | | | | |
| 79 | 10240 | 1.95 | 97.66 | G2 | 98.00 | 0.34 | 0.35 |
| 80 | 10368 | 1.93 | 96.45 | | | | |
| 81 | 10496 | 1.91 | 95.27 | | | | |
| 82 | 10624 | 1.88 | 94.13 | | | | |
| 83 | 10752 | 1.86 | 93.01 | F♯2 | 92.50 | -0.51 | -0.55 |
| 84 | 10880 | 1.84 | 91.91 | | | | |
| 85 | 11008 | 1.82 | 90.84 | | | | |
| 86 | 11136 | 1.80 | 89.80 | | | | |
| 87 | 11264 | 1.78 | 88.78 | | | | |
| 88 | 11392 | 1.76 | 87.78 | F2 | 87.31 | -0.47 | -0.54 |
| 89 | 11520 | 1.74 | 86.81 | | | | |
| 90 | 11648 | 1.72 | 85.85 | | | | |
| 91 | 11776 | 1.70 | 84.92 | | | | |
| 92 | 11904 | 1.68 | 84.01 | | | | |
| 93 | 12032 | 1.66 | 83.11 | | | | |
| 94 | 12160 | 1.64 | 82.24 | E2 | 82.41 | 0.17 | 0.21 |
| 95 | 12288 | 1.63 | 81.38 | | | | |
| 96 | 12416 | 1.61 | 80.54 | | | | |
| 97 | 12544 | 1.59 | 79.72 | | | | |
| 98 | 12672 | 1.58 | 78.91 | | | | |
| 99 | 12800 | 1.56 | 78.13 | | | | |
| 100 | 12928 | 1.55 | 77.35 | D♯2 | 77.78 | 0.43 | 0.55 |
| 101 | 13056 | 1.53 | 76.59 | | | | |
| 102 | 13184 | 1.52 | 75.85 | | | | |
| 103 | 13312 | 1.50 | 75.12 | | | | |
| 104 | 13440 | 1.49 | 74.40 | | | | |
| 105 | 13568 | 1.47 | 73.70 | D2 | 73.42 | -0.28 | -0.39 |
| 106 | 13696 | 1.46 | 73.01 | | | | |
| 107 | 13824 | 1.45 | 72.34 | | | | |
| 108 | 13952 | 1.43 | 71.67 | | | | |
| 109 | 14080 | 1.42 | 71.02 | | | | |
| 110 | 14208 | 1.41 | 70.38 | | | | |
| 111 | 14336 | 1.40 | 69.75 | | | | |
| 112 | 14464 | 1.38 | 69.14 | C♯2 | 69.30 | 0.16 | 0.23 |
| 113 | 14592 | 1.37 | 68.53 | | | | |
| 114 | 14720 | 1.36 | 67.93 | | | | |
| 115 | 14848 | 1.35 | 67.35 | | | | |
| 116 | 14976 | 1.34 | 66.77 | | | | |
| 117 | 15104 | 1.32 | 66.21 | | | | |
| 118 | 15232 | 1.31 | 65.65 | C2 | 65.41 | -0.24 | -0.37 |
| 119 | 15360 | 1.30 | 65.10 | | | | |
| 120 | 15488 | 1.29 | 64.57 | | | | |
| 121 | 15616 | 1.28 | 64.04 | | | | |
| 122 | 15744 | 1.27 | 63.52 | | | | |
| 123 | 15872 | 1.26 | 63.00 | | | | |
| 124 | 16000 | 1.25 | 62.50 | | | | |
| 125 | 16128 | 1.24 | 62.00 | | | | |
| 126 | 16256 | 1.23 | 61.52 | B1 | 61.74 | 0.22 | 0.36 |
| 127 | 16384 | 1.22 | 61.04 | | | | |
| 128 | 16512 | 1.21 | 60.56 | | | | |
| 129 | 16640 | 1.20 | 60.10 | | | | |
| 130 | 16768 | 1.19 | 59.64 | | | | |
| 131 | 16896 | 1.18 | 59.19 | | | | |
| 132 | 17024 | 1.17 | 58.74 | | | | |
| 133 | 17152 | 1.17 | 58.30 | A♯1 | 58.27 | -0.03 | -0.06 |
| 134 | 17280 | 1.16 | 57.87 | | | | |
| 135 | 17408 | 1.15 | 57.44 | | | | |
| 136 | 17536 | 1.14 | 57.03 | | | | |
| 137 | 17664 | 1.13 | 56.61 | | | | |
| 138 | 17792 | 1.12 | 56.21 | | | | |
| 139 | 17920 | 1.12 | 55.80 | | | | |
| 140 | 18048 | 1.11 | 55.41 | | | | |
| 141 | 18176 | 1.10 | 55.02 | A1 | 55.00 | -0.02 | -0.03 |
| 142 | 18304 | 1.09 | 54.63 | | | | |
| 143 | 18432 | 1.09 | 54.25 | | | | |
| 144 | 18560 | 1.08 | 53.88 | | | | |
| 145 | 18688 | 1.07 | 53.51 | | | | |
| 146 | 18816 | 1.06 | 53.15 | | | | |
| 147 | 18944 | 1.06 | 52.79 | | | | |
| 148 | 19072 | 1.05 | 52.43 | | | | |
| 149 | 19200 | 1.04 | 52.08 | G♯1 | 51.91 | -0.17 | -0.33 |
| 150 | 19328 | 1.03 | 51.74 | | | | |
| 151 | 19456 | 1.03 | 51.40 | | | | |
| 152 | 19584 | 1.02 | 51.06 | | | | |
| 153 | 19712 | 1.01 | 50.73 | | | | |
| 154 | 19840 | 1.01 | 50.40 | | | | |
| 155 | 19968 | 1.00 | 50.08 | | | | |
| 156 | 20096 | 1.00 | 49.76 | | | | |
| 157 | 20224 | 0.99 | 49.45 | | | | |
| 158 | 20352 | 0.98 | 49.14 | G1 | 49.00 | -0.14 | -0.28 |
| 159 | 20480 | 0.98 | 48.83 | | | | |
| 160 | 20608 | 0.97 | 48.52 | | | | |
| 161 | 20736 | 0.96 | 48.23 | | | | |
| 162 | 20864 | 0.96 | 47.93 | | | | |
| 163 | 20992 | 0.95 | 47.64 | | | | |
| 164 | 21120 | 0.95 | 47.35 | | | | |
| 165 | 21248 | 0.94 | 47.06 | | | | |
| 166 | 21376 | 0.94 | 46.78 | | | | |
| 167 | 21504 | 0.93 | 46.50 | | | | |
| 168 | 21632 | 0.92 | 46.23 | F♯1 | 46.25 | 0.02 | 0.05 |
| 169 | 21760 | 0.92 | 45.96 | | | | |
| 170 | 21888 | 0.91 | 45.69 | | | | |
| 171 | 22016 | 0.91 | 45.42 | | | | |
| 172 | 22144 | 0.90 | 45.16 | | | | |
| 173 | 22272 | 0.90 | 44.90 | | | | |
| 174 | 22400 | 0.89 | 44.64 | | | | |
| 175 | 22528 | 0.89 | 44.39 | | | | |
| 176 | 22656 | 0.88 | 44.14 | | | | |
| 177 | 22784 | 0.88 | 43.89 | | | | |
| 178 | 22912 | 0.87 | 43.65 | F1 | 43.65 | 0.00 | 0.01 |
| 179 | 23040 | 0.87 | 43.40 | | | | |
| 180 | 23168 | 0.86 | 43.16 | | | | |
| 181 | 23296 | 0.86 | 42.93 | | | | |
| 182 | 23424 | 0.85 | 42.69 | | | | |
| 183 | 23552 | 0.85 | 42.46 | | | | |
| 184 | 23680 | 0.84 | 42.23 | | | | |
| 185 | 23808 | 0.84 | 42.00 | | | | |
| 186 | 23936 | 0.84 | 41.78 | | | | |
| 187 | 24064 | 0.83 | 41.56 | | | | |
| 188 | 24192 | 0.83 | 41.34 | | | | |
| 189 | 24320 | 0.82 | 41.12 | E1 | 41.20 | 0.08 | 0.20 |
| 190 | 24448 | 0.82 | 40.90 | | | | |
| 191 | 24576 | 0.81 | 40.69 | | | | |
| 192 | 24704 | 0.81 | 40.48 | | | | |
| 193 | 24832 | 0.81 | 40.27 | | | | |
| 194 | 24960 | 0.80 | 40.06 | | | | |
| 195 | 25088 | 0.80 | 39.86 | | | | |
| 196 | 25216 | 0.79 | 39.66 | | | | |
| 197 | 25344 | 0.79 | 39.46 | | | | |
| 198 | 25472 | 0.79 | 39.26 | | | | |
| 199 | 25600 | 0.78 | 39.06 | | | | |
| 200 | 25728 | 0.78 | 38.87 | D♯1 | 38.89 | 0.02 | 0.06 |
| 201 | 25856 | 0.77 | 38.68 | | | | |
| 202 | 25984 | 0.77 | 38.49 | | | | |
| 203 | 26112 | 0.77 | 38.30 | | | | |
| 204 | 26240 | 0.76 | 38.11 | | | | |
| 205 | 26368 | 0.76 | 37.92 | | | | |
| 206 | 26496 | 0.75 | 37.74 | | | | |
| 207 | 26624 | 0.75 | 37.56 | | | | |
| 208 | 26752 | 0.75 | 37.38 | | | | |
| 209 | 26880 | 0.74 | 37.20 | | | | |
| 210 | 27008 | 0.74 | 37.03 | | | | |
| 211 | 27136 | 0.74 | 36.85 | | | | |
| 212 | 27264 | 0.73 | 36.68 | D1 | 36.71 | 0.03 | 0.09 |
| 213 | 27392 | 0.73 | 36.51 | | | | |
| 214 | 27520 | 0.73 | 36.34 | | | | |
| 215 | 27648 | 0.72 | 36.17 | | | | |
| 216 | 27776 | 0.72 | 36.00 | | | | |
| 217 | 27904 | 0.72 | 35.84 | | | | |
| 218 | 28032 | 0.71 | 35.67 | | | | |
| 219 | 28160 | 0.71 | 35.51 | | | | |
| 220 | 28288 | 0.71 | 35.35 | | | | |
| 221 | 28416 | 0.70 | 35.19 | | | | |
| 222 | 28544 | 0.70 | 35.03 | | | | |
| 223 | 28672 | 0.70 | 34.88 | | | | |
| 224 | 28800 | 0.69 | 34.72 | C♯1 | 34.65 | -0.07 | -0.21 |
| 225 | 28928 | 0.69 | 34.57 | | | | |
| 226 | 29056 | 0.69 | 34.42 | | | | |
| 227 | 29184 | 0.69 | 34.27 | | | | |
| 228 | 29312 | 0.68 | 34.12 | | | | |
| 229 | 29440 | 0.68 | 33.97 | | | | |
| 230 | 29568 | 0.68 | 33.82 | | | | |
| 231 | 29696 | 0.67 | 33.67 | | | | |
| 232 | 29824 | 0.67 | 33.53 | | | | |
| 233 | 29952 | 0.67 | 33.39 | | | | |
| 234 | 30080 | 0.66 | 33.24 | | | | |
| 235 | 30208 | 0.66 | 33.10 | | | | |
| 236 | 30336 | 0.66 | 32.96 | | | | |
| 237 | 30464 | 0.66 | 32.83 | | | | |
| 238 | 30592 | 0.65 | 32.69 | C1 | 32.70 | 0.01 | 0.04 |
| 239 | 30720 | 0.65 | 32.55 | | | | |
| 240 | 30848 | 0.65 | 32.42 | | | | |
| 241 | 30976 | 0.65 | 32.28 | | | | |
| 242 | 31104 | 0.64 | 32.15 | | | | |
| 243 | 31232 | 0.64 | 32.02 | | | | |
| 244 | 31360 | 0.64 | 31.89 | | | | |
| 245 | 31488 | 0.64 | 31.76 | | | | |
| 246 | 31616 | 0.63 | 31.63 | | | | |
| 247 | 31744 | 0.63 | 31.50 | | | | |
| 248 | 31872 | 0.63 | 31.38 | | | | |
| 249 | 32000 | 0.63 | 31.25 | | | | |
| 250 | 32128 | 0.62 | 31.13 | | | | |
| 251 | 32256 | 0.62 | 31.00 | | | | |
| 252 | 32384 | 0.62 | 30.88 | B0 | 30.87 | -0.01 | -0.03 |
| 253 | 32512 | 0.62 | 30.76 | | | | |
| 254 | 32640 | 0.61 | 30.64 | | | | |
| 255 | 32768 | 0.61 | 30.52 | | | | |

## PVI integers and indexes chart

PVI integer (index number) :
| Note\Octave | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| C | | 238(1) | 118(13) | 59(25) | 29(37) | 14(49) | | |
| C♯/D♭ | | 224(2) | 112(14) | 55(26) | 27(38) | 13(50) | 6(62) | |
| D | | 212(3) | 105(15) | 52(27) | 26(39) | 12(51) | | |
| E♭/D♯ | | 200(4) | 100(16) | 49(28) | 24(40) | | | |
| E | | 189(5) | 94(17) | 46(29) | 23(41) | 11(53) | 5(65) | 2(77) |
| F | | 178(6) | 88(18) | 44(30) | 21(42) | 10(54) | | |
| F♯/G♭ | | 168(7) | 83(19) | 41(31) | 20(43) | | | |
| G | | 158(8) | 79(20) | 39(32) | 19(44) | 9(56) | 4(68) | |
| A♭/G♯ | | 149(9) | 74(21) | 37(33) | 18(45) | | | |
| A | | 141(10) | 70(22) | 35(34) | 17(46) | 8(58) | | |
| B♭/A♯ | | 133(11) | 66(23) | 33(35) | 16(47) | | | |
| B | 252(0) | 126(12) | 63(24) | 31(36) | 15(48) | 7(60) | 3(72) | 1(84) |

## Coded index table

This table is just one way of implementing an index table to look up integer values corresponding to a musical note to feed to the PVI sound register $1FC7. Each unit step in index value shift by one semitone. Stepping by 12 in the index value shifts by an octave.
The lookup table uses 85 bytes and covers the range B0 to B7 but could be shrunk by reducing the range, or by eliminating notes not used in the composition. Note that beyond D5 many notes are not available.

## References

* ↑ https://pages.mtu.edu/~suits/notefreqs.html