[Discuss-gnuradio] USRP Tx and Rx IF sample rates

[Eric Blossom]

On Fri, Feb 18, 2005 at 05:49:26PM -0500, Bob Vincent wrote:
> Could you enumerate some of those possible rates here?
> I think we at least would find it useful to change rates.

Below are tables of acceptable Tx and Rx IF sample rates.

A couple of notes are in order.  Matt's going to be making a change to
the FPGA that adds a half-band filter to the Tx and Rx paths.  This is
a good thing (better alias rejection, flatter passband), but adds an
additional factor of 2 constraint to the acceptable interpolation and
decimation rates.  The tables below reflect settings that are
acceptable under both the current and future scenarios.

Second, remember that you have a limit based on your USB throughput
(current best case 32MB/sec).  Each complex sample is 4 bytes.  If you
are running full-duplex or running more than a single Tx or Rx channel
you'll need to take that into account.


If you want to see all the tables, run this:

#!/usr/bin/env python

def print_table (start, stop, multiple, freq):
    for x in range(start,stop+multiple,multiple):
        print "%3d\t%13.4f" % (x, freq/x)

print "Tx Rates (now)"
print_table (4,512,4,128e6)

print "Tx Rates (future)"
print_table (8,1024,8,128e6)

print "Rx Rates (now)"
print_table (1,256,1,64e6)

print "Rx Rates (future)"
print_table (2,512,2,64e6)

----------------------------------------------------------------

Acceptable Tx IF sample rates
Interp     Samples/sec
====    ===============
 16      8,000,000.0000
 24      5,333,333.3333
 32      4,000,000.0000
 40      3,200,000.0000 
 48      2,666,666.6667
 56      2,285,714.2857
 64      2,000,000.0000
 72      1,777,777.7778
 80      1,600,000.0000
 88      1,454,545.4545
 96      1,333,333.3333
104      1,230,769.2308
112      1,142,857.1429
120      1,066,666.6667
128      1,000,000.0000
136        941,176.4706
144        888,888.8889
152        842,105.2632
160        800,000.0000
168        761,904.7619
176        727,272.7273
184        695,652.1739
192        666,666.6667
200        640,000.0000
208        615,384.6154
216        592,592.5926
224        571,428.5714
232        551,724.1379
240        533,333.3333
248        516,129.0323
256        500,000.0000
264        484,848.4848
272        470,588.2353
280        457,142.8571
288        444,444.4444
296        432,432.4324
304        421,052.6316
312        410,256.4103
320        400,000.0000
328        390,243.9024
336        380,952.3810
344        372,093.0233
352        363,636.3636
360        355,555.5556
368        347,826.0870
376        340,425.5319
384        333,333.3333
392        326,530.6122
400        320,000.0000
408        313,725.4902
416        307,692.3077
424        301,886.7925
432        296,296.2963
440        290,909.0909
448        285,714.2857
456        280,701.7544
464        275,862.0690
472        271,186.4407
480        266,666.6667
488        262,295.0820
496        258,064.5161
504        253,968.2540
512        250,000.0000

Acceptable Rx IF sample rates
Decim      Samples/sec
====    =============
  8      8,000,000.0000
 10      6,400,000.0000
 12      5,333,333.3333
 14      4,571,428.5714
 16      4,000,000.0000
 18      3,555,555.5556
 20      3,200,000.0000
 22      2,909,090.9091
 24      2,666,666.6667
 26      2,461,538.4615
 28      2,285,714.2857
 30      2,133,333.3333
 32      2,000,000.0000
 34      1,882,352.9412
 36      1,777,777.7778
 38      1,684,210.5263
 40      1,600,000.0000
 42      1,523,809.5238
 44      1,454,545.4545
 46      1,391,304.3478
 48      1,333,333.3333
 50      1,280,000.0000
 52      1,230,769.2308
 54      1,185,185.1852
 56      1,142,857.1429
 58      1,103,448.2759
 60      1,066,666.6667
 62      1,032,258.0645
 64      1,000,000.0000
 66        969,696.9697
 68        941,176.4706
 70        914,285.7143
 72        888,888.8889
 74        864,864.8649
 76        842,105.2632
 78        820,512.8205
 80        800,000.0000
 82        780,487.8049
 84        761,904.7619
 86        744,186.0465
 88        727,272.7273
 90        711,111.1111
 92        695,652.1739
 94        680,851.0638
 96        666,666.6667
 98        653,061.2245
100        640,000.0000
102        627,450.9804
104        615,384.6154
106        603,773.5849
108        592,592.5926
110        581,818.1818
112        571,428.5714
114        561,403.5088
116        551,724.1379
118        542,372.8814
120        533,333.3333
122        524,590.1639
124        516,129.0323
126        507,936.5079
128        500,000.0000
130        492,307.6923
132        484,848.4848
134        477,611.9403
136        470,588.2353
138        463,768.1159
140        457,142.8571
142        450,704.2254
144        444,444.4444
146        438,356.1644
148        432,432.4324
150        426,666.6667
152        421,052.6316
154        415,584.4156
156        410,256.4103
158        405,063.2911
160        400,000.0000
162        395,061.7284
164        390,243.9024
166        385,542.1687
168        380,952.3810
170        376,470.5882
172        372,093.0233
174        367,816.0920
176        363,636.3636
178        359,550.5618
180        355,555.5556
182        351,648.3516
184        347,826.0870
186        344,086.0215
188        340,425.5319
190        336,842.1053
192        333,333.3333
194        329,896.9072
196        326,530.6122
198        323,232.3232
200        320,000.0000
202        316,831.6832
204        313,725.4902
206        310,679.6117
208        307,692.3077
210        304,761.9048
212        301,886.7925
214        299,065.4206
216        296,296.2963
218        293,577.9817
220        290,909.0909
222        288,288.2883
224        285,714.2857
226        283,185.8407
228        280,701.7544
230        278,260.8696
232        275,862.0690
234        273,504.2735
236        271,186.4407
238        268,907.5630
240        266,666.6667
242        264,462.8099
244        262,295.0820
246        260,162.6016
248        258,064.5161
250        256,000.0000
252        253,968.2540
254        251,968.5039
256        250,000.0000