diff options
| author | Tom Rondeau <tom@trondeau.com> | 2015-08-17 12:26:24 -0400 |
|---|---|---|
| committer | Tom Rondeau <tom@trondeau.com> | 2015-08-17 12:26:24 -0400 |
| commit | dff90672879bf1ed9d3e083ba236fdd6ce29e168 (patch) | |
| tree | 7b066b9aa14af2758a515d6a4c3c2ea137cf2a24 /gr-digital/python/digital/soft_dec_lut_gen.py | |
| parent | 22e2f1aed8afdfccce3884cf6bf3140c2b8e3f53 (diff) | |
whitespace fixes and some minor adjustments for building the Python
manual.
Diffstat (limited to 'gr-digital/python/digital/soft_dec_lut_gen.py')
| -rw-r--r-- | gr-digital/python/digital/soft_dec_lut_gen.py | 109 |
1 files changed, 55 insertions, 54 deletions
diff --git a/gr-digital/python/digital/soft_dec_lut_gen.py b/gr-digital/python/digital/soft_dec_lut_gen.py index 5bea27f843..f517277702 100644 --- a/gr-digital/python/digital/soft_dec_lut_gen.py +++ b/gr-digital/python/digital/soft_dec_lut_gen.py @@ -23,60 +23,61 @@ import numpy def soft_dec_table_generator(soft_dec_gen, prec, Es=1): - '''Builds a LUT that is a list of tuples. The tuple represents the - soft decisions for the constellation/bit mapping at any given - point in the complex space, (x,y). - - The table is built to a precision specified by the 'prec' - argument. There are (2x2)^prec samples in the sample space, so we - get the precision of 2^prec samples in both the real and imaginary - axes. - - The space is represented where index 0 is the bottom left corner - and the maximum index is the upper left. The table index for a - surface space with 4 bits of precision looks like the following: - - 240 241 242 243 244 245 246 247 | 248 249 250 251 252 253 254 255 - 224 225 226 227 228 229 230 231 | 232 233 234 235 236 237 238 239 - 208 209 210 211 212 213 214 215 | 216 217 218 219 220 221 222 223 - 192 193 194 195 196 197 198 199 | 200 201 202 203 204 205 206 207 - 176 177 178 179 180 181 182 183 | 184 185 186 187 188 189 190 191 - 160 161 162 163 164 165 166 167 | 168 169 170 171 172 173 174 175 - 144 145 146 147 148 149 150 151 | 152 153 154 155 156 157 158 159 - 128 129 130 131 132 133 134 135 | 136 137 138 139 140 141 142 143 - ----------------------------------------------------------------- - 112 113 114 115 116 117 118 119 | 120 121 122 123 124 125 126 127 - 96 97 98 99 100 101 102 103 | 104 105 106 107 108 109 110 111 - 80 81 82 83 84 85 86 87 | 88 89 90 91 92 93 94 95 - 64 65 66 67 68 69 70 71 | 72 73 74 75 76 77 78 79 - 48 49 50 51 52 53 54 55 | 56 57 58 59 60 61 62 63 - 32 33 34 35 36 37 38 39 | 40 41 42 43 44 45 46 47 - 16 17 18 19 20 21 22 23 | 24 25 26 27 28 29 30 31 - 0 1 2 3 4 5 6 7 | 8 9 10 11 12 13 14 15 - - We then calculate coordinates from -1 to 1 with 2^prec points for - both the x and y axes. We then sample starting at (-1, -1) and - move left to right on the x-axis and then move up a row on the - y-axis. For every point in this sampled space, we calculate the - soft decisions for the given constellation/mapping. This is done - by passing in the function 'soft_dec_gen' as an argument to this - function. This takes in the x/y coordinates and outputs the soft - decisions. These soft decisions are stored into the list at the - index from the above table as a tuple. - - The function 'calc_from_table' takes in a point and reverses this - operation. It converts the point from the coordinates (-1,-1) to - (1,1) into an index value in the table and returns the tuple of - soft decisions at that index. - - Es is the maximum energy per symbol. This is passed to the - function to provide the bounds when calling the generator function - since they don't know how the constellation was normalized. Using - the (maximum) energy per symbol for constellation allows us to - provide any scaling of the constellation (normalized to sum to 1, - normalized so the outside points sit on +/-1, etc.) but still - calculate the soft decisions as we would given the full - constellation. + ''' + | Builds a LUT that is a list of tuples. The tuple represents the + | soft decisions for the constellation/bit mapping at any given + | point in the complex space, (x,y). + | + | The table is built to a precision specified by the 'prec' + | argument. There are (2x2)^prec samples in the sample space, so we + | get the precision of 2^prec samples in both the real and imaginary + | axes. + | + | The space is represented where index 0 is the bottom left corner + | and the maximum index is the upper left. The table index for a + | surface space with 4 bits of precision looks like the following: + | + | 240 241 242 243 244 245 246 247 | 248 249 250 251 252 253 254 255 + | 224 225 226 227 228 229 230 231 | 232 233 234 235 236 237 238 239 + | 208 209 210 211 212 213 214 215 | 216 217 218 219 220 221 222 223 + | 192 193 194 195 196 197 198 199 | 200 201 202 203 204 205 206 207 + | 176 177 178 179 180 181 182 183 | 184 185 186 187 188 189 190 191 + | 160 161 162 163 164 165 166 167 | 168 169 170 171 172 173 174 175 + | 144 145 146 147 148 149 150 151 | 152 153 154 155 156 157 158 159 + | 128 129 130 131 132 133 134 135 | 136 137 138 139 140 141 142 143 + | ----------------------------------------------------------------- + | 112 113 114 115 116 117 118 119 | 120 121 122 123 124 125 126 127 + | 96 97 98 99 100 101 102 103 | 104 105 106 107 108 109 110 111 + | 80 81 82 83 84 85 86 87 | 88 89 90 91 92 93 94 95 + | 64 65 66 67 68 69 70 71 | 72 73 74 75 76 77 78 79 + | 48 49 50 51 52 53 54 55 | 56 57 58 59 60 61 62 63 + | 32 33 34 35 36 37 38 39 | 40 41 42 43 44 45 46 47 + | 16 17 18 19 20 21 22 23 | 24 25 26 27 28 29 30 31 + | 0 1 2 3 4 5 6 7 | 8 9 10 11 12 13 14 15 + | + | We then calculate coordinates from -1 to 1 with 2^prec points for + | both the x and y axes. We then sample starting at (-1, -1) and + | move left to right on the x-axis and then move up a row on the + | y-axis. For every point in this sampled space, we calculate the + | soft decisions for the given constellation/mapping. This is done + | by passing in the function 'soft_dec_gen' as an argument to this + | function. This takes in the x/y coordinates and outputs the soft + | decisions. These soft decisions are stored into the list at the + | index from the above table as a tuple. + | + | The function 'calc_from_table' takes in a point and reverses this + | operation. It converts the point from the coordinates (-1,-1) to + | (1,1) into an index value in the table and returns the tuple of + | soft decisions at that index. + | + | Es is the maximum energy per symbol. This is passed to the + | function to provide the bounds when calling the generator function + | since they don't know how the constellation was normalized. Using + | the (maximum) energy per symbol for constellation allows us to + | provide any scaling of the constellation (normalized to sum to 1, + | normalized so the outside points sit on +/-1, etc.) but still + | calculate the soft decisions as we would given the full + | constellation. ''' |