Torpedo Striker Overview

Attenuation Ytorpedo)-(15+(Xtorpedo)=Dis 22 ) ((-Dis/15)2e=G

Balance

***Normalized to one in codeRightGain-4=LeftGain

2e=RightGain ) rpedo)/5)((-abs(Xto

Overall Falloff

Sonar Sound Generation I

• Quality sound from Dr. Kepuska (exp based)• Too much processing time

Sonar Sound Generation II

• Less quality sound I developed (sinc based)• Still too much processing time

function [xg] = SonarSynthe(fs, dur, varargin);d = dur*fs; % dur in sec t = 0:d; % t in number of samplesh=2*pi*(8*t./fs-0.6);xx=2*sin(h)./h+0.6;decayz=exp(-3*t./fs);env1=xx.*decayz;chime=exp(-3*t./fs).*sin(2*pi*62*t./fs);env2=env1+chime+1.5;env3=env2.*0.3.*exp(-3*t./fs);fc=1500;x=sin(2*pi*fc.*t./(fs*dur));xg=x.*env3;figure; plot(t./fs,xg); grid on; xlabel('Time [s]'); title('Sythesised Signal');soundsc(xg, fs);

Sonar Sound Generation III

• Linear falloff to avoid exp calculations• Now recognizable on DSP, but not perfect

Sonar Sound Generation IV

• Output Dr. Kepuska’s sound from Matlab as array and store in SDRAM

• Cycle through array elements at sampling frequency for playback

Sub Noise

• Background noise for continual sense of location

• Low frequency 300Hz tone• y=sin(2*pi*300*t./d)

Dead Beat Tone

• To signify a torpedo miss• Single 1200Hz tone like dead beat life support• y=sin(2*pi*1200*t./d);

Explosion Noise I

• Random number generation for sine wave• Linear interpolation between random number

generation• model

tte

Explosion Noise II• void (Explosiond)(void)• {• scalar=(statrand/35);• c = (long)((co-cprev)*scalar + cprev); // linear interpolation… y=mx+b • randfunc=cosf(2*pi*c/ 1073741823);• decay2=2*(te/d2)*expf(-3*(te)/fs);• z=decay2*randfunc;• z=z*40000000;•• scalar2=(statrand2/75);• c2 = (long)((co2-cprev2)*scalar2 + cprev2);• randfunc2=cosf(2*pi*c2/ 1073741823);• decay2b=4*(te/d2)*expf(-3*(te+2)/fs);• z2=decay2*randfunc2;• z2=z2*40000000;

• te=te+1;• statrand = statrand +1;• statrand2 = statrand2 +1;• if (statrand >= 35)• { statrand=1;• cprev=co;• srand(te);• co=rand();• }• if (statrand2 >= 75)• { statrand2=1;• cprev2=co2;• srand(te+1);• co2=rand();• }• if (te >d)• {• te =0;• exptrig=0;• }• z=z+z2;• iChannel0LeftIn = (int) z;• iChannel0RightIn = (int) z;•• }

Problems

• Processing time and real time audio– Overcome with simplified algorithms and stored

audio in SDRAM

• Intermittent Ping– Added background noise for sense of location

Concluding Remarks

• Design of Torpedo Striker has been rewarding process

• Special thanks to Dr. Kepuska for Sonar Sound and additional help

• Special thanks to Za and SDRAM help

Questions?