bench.txt

来自「利用ti54x系列dsp编解码dtmf源程序的第三版」· 文本 代码 · 共 116 行

-----------------------------------------------------------------
Benchmarks for modified C54x DTMF codec (Rev. 3.0)
-----------------------------------------------------------------

This is the modified code of the the one described in the appnote.
The following changes have been made.

(1) the code is fully reentrant, and C-callable
    multiple channel decoder is easily setup in C

(2) buffered concept (as opposed to sample by sample)
    advantage is MIPS count reduction by 50%
    disadvantage is an increased DATA memory requirement of approx
    242 words per channel due to double buffering of data

(3) no overflow check needed due to improved gain control

(4) improved digit validation tests offer greater robustness

(5) conditional computation of 2nd harmonic frequencies
    further MIPS count reduction by approx 30%

(6) Integrated DTMF tone generator
    c-callable, can coexist with DTMF detector



****************************************************************
******    Benchmarks for DTMF decoder                   ********
****************************************************************

******** MIPS counts **********
The given MIPS counts are for a single channel decoder. The decoder
is capable of decoding 16 frequencies (4 row, 4 column, 8 2nd harmonics).
Sampling rate is assumed to be 8 kHz.

- DTMF algorithm based on Goertzel-DFT
					Cycles per	Processor load
					102 samples	in MIPS
					data block

	Overhead (can vary)		  100 cycles	0.008 MIPS
	gaincontrol function		  575 cycles	0.045 MIPS
	goertzel-function		 4637 cycles	0.363 MIPS
	DTMF-digit validation	  	 1544 cycles	0.121 MIPS
					--------------------------
	TOTAL (per full DTMF channel)	 6865 cycles	0.54  MIPS


******** Memory utilization *********
Assumed are n=16 frequencies.

- DATA space
	data buffer			102*n
	taps template			 20*n
	energy template			 10*n
	variables			  8*n
	coefficients			 16
	keys template			 16
					--------
	TOTAL (n channels)		140*n+32

  The DATA space requirements increase are due to the buffering of 
  a 102 samples data block per channel. The functions will operate 
  on these data buffers as opposed to a sample by sample concept.
	
- PROG space
	main, subroutines		589 words
	ISRs, inits, C-environment	351 words
					---------
	TOTAL				940 words

******** Performance *****************
successfully tested to MITEL digit test
successfully tested to MITEL talk-off
successfully tested to BELLCORE talk-off




****************************************************************
******    Benchmarks for DTMF encoder                   ********
****************************************************************

******** MIPS counts **********
Sampling rate is assumed to be 8 kHz.

					Cycles per	Processor load
					102 samples	in MIPS
					data block

	Overhead (can vary)		  100 cycles	0.008 MIPS
	DTMF tone generation	  	 1790 cycles	0.140 MIPS
					--------------------------
	TOTAL (per full DTMF channel)	 6865 cycles	0.148  MIPS

******** Memory utilization *********
Assumed are n=16 frequencies.

- DATA space
	data buffer (**)		102*n
	oscillator states		 16*n
	variables			  9*n
	coefficients			  8
	keys template (***)		 16
					--------
	TOTAL (n channels)		127*n+24

	(**)  this can be the same buffer used for the decoder.
	(***) this can be the same keys template used for the decoder.

- PROG space
	encoder subroutines		198 words
					---------
	TOTAL				198 words