THERE ARE MANY SIMPLE THINGS WHICH YOU CAN DO LIKE UH QUANTIZATION QUANTIZATION FOR EXAMPLE LIKE BECAUSE YOU'VE GOT A NICE SCALABLE SCHEME FOR THE FOR FOR THE THE CODING OF THE THE SMOOTH SPECTRUM IT'D BE NICE TO HAVE SOME SORT OF SCALABLE CODING SCHEME FOR THE FOR THE VOICE SIGNAL AS WELL RIGHT HMM WELL I DON'T KNOW I'M JUST WHAT YOU MEAN BY THAT SO THE ACTUAL UH EXCITATION AS WELL BECAUSE I MEAN IT'D BE NICE UH L LET'S SAY IF YOU HAD TWELVE HUNDRED BITS FOR THE FOR THE SP SMOOTH SPECTRUM AND TWELVE HUNDRED BITS FOR THE VOICE AND THEN YOU COULD SCALE THEM BOTH YEAH SURE SURE SURE YEAH I HAVE A QUESTION IS THE SCALE LINEAR OR IS MEL SCALE LIKE IN M. F. C. C. IS IT BAR SCALE LIKE IN LIKE IN SP YEAH OKAY OH YEAH TYPE THE OVERLAPPING IS DIFFERENT RIGHT YEP MM BUT WHAT I W MY SENSE IS THAT IT IS NOT SO MUCH IMPORTANT STILL I MEAN IT DOESN'T MATTER IF YOU'RE ALS USE MEL SCALE OR BAR SCALE BUT RIGHT YEAH BUT THAT'S WHAT WE ARE USING YEAH UH ACTUALLY WE ARE USING JUST GAUSSIAN WINDOWS HERE INSTEAD OF THOSE TRIANGULARS BECAUSE THEY ARE MORE UH NO IT'S BETTER THAN FOR DECODING IT'S BETTER TO PLAY WITH THEM BECAUSE THEY THEY ARE NOT ZERO ANYWHERE YOU KNOW YEAH YEAH YEAH HMM BUT ACTUALLY THEY ARE NOT SO D YOU DON'T HAVE TO CARE ABOUT SOME ZERO VALUES HERE AND BUT MORE OR LESS IT DOESN'T MATTER YEAH WE ARE USING JUST GAUS GAUSSIAN WINDOWS OKAY SO AFTER YOU'RE DOING L. S. F. S SO OR LIKE I MEAN HOW YOU'RE FINALLY HAND CODING AH OH AND THEN VECTOR QUANTIZE OR WHATEVER YEAH SO FIRST YOU APPLY THESE TRIANGLE FILTERS AND THEN DO L. P. C. CODING OR LIKE RIGHT EXACTLY SO FIRST UH THE APPROACH IS QUITE SIM SIMPLE SO AT THE BEGINNING WE APPLY D. C. T. IN ORDER TO GET TO FREQUENCY DOMAIN THEN YOU APPLY THOSE UH TRIANGULAR OR GAUSSIAN WINDOWS SO THIS IS DONE FOR ONE SECOND EIGHT THOUSAND SAMPLES FOR EIGHT KILO HERTZ SAMPLING FREQUENCY RIGHT SO FOR SUCH D. C. T. TRAJECTORY YOU APPLY THOSE UH GAUSSIAN WINDOWS AND THEN I SO YOU SPLIT IT IN TWO FREQUENCY SUB BANDS AND THEN EACH ONE F FREQUENCY SUB BAND IS MORE OR LESS UH YOU CAN DO THE L. P. ANALYSIS ON EACH SUB BAND YEAH YEAH M YEAH OK YEAH YEAH YEAH YEAH YEAH SO HOW MANY L. S. F. S YOU'RE USING AND SO TIMES FIFTEEN TWEN THAT'S T IT'S TWENTY TIMES FIFTEEN IT'S NOT NO NO IF I JUST KEEP ALL THEM SO TWENTY L. S. F. S EACH ONE IS UM HMM IS QUANTIZED BY FOUR OR FIVE BITS OKAY SO IT'S IT'S YEAH IT'S THREE HUNDRED OF WHAT THREE HUNDRED BITS OH YEAH UM TWO YEAH YEAH YEAH YEAH EXACTLY PHASE YOU'RE DIRECTLY TRANSMITTING THAT UH NO TH YEAH YEAH YEAH THE PHASE OF HILBERT ENVELOPE YEAH I UH UH W WELL THERE ARE MANY THINGS YOU CAN DO WE DON'T WELL THE FIRST THING WHAT YOU CAN REALLY DO IS JUST TO REPLACE IT BY GAUSSIAN NOISE SO YOU CAN REALLY USE T LIKE IN UH L. P. C. SYSTEM RIGHT EXACTLY OR YOU CAN REPLACE IT BY SOME COSINE ONE COSINE GENERATED IN A CEN CENTRE FREQUENCY OF THAT GAUSSIAN WINDOW YEAH RIGHT YEAH IF YOU'RE GOING TO AIM FOR LIKE A VERY LOW RATE CODE TO BELOW FIVE HUNDRED BITS PER SECOND I GUESS THAT'S THAT'S PROBABLY FINE BUT LIKE IT'S IT'S TWO KILO BITS PER SECOND OR THE OH THAT TWO TWO KILO BITS PER T AH OK AH SOME YEAH YEAH IT'S POSSIBLE SOME OF IT YEAH MM-HMM YEAH YEAH BUT R RIGHT BUT I MEAN I IMAGINE THE SAME SORT OF APPROACH COULD BE TAKEN WITH YOURS AS WELL A LITTLE BIT OPTIMIZED SO THERE IN THE THERE IS I THINK TWO POINT FOUR KILO BITS PER SECOND THE BIT RATE FOR THAT TWENTY MELP*'S A LOT BETTER QUALITY THOUGH YEAH THIS IS NO UH I MEAN L. P. C. TEN IS JUST L. P. C. NO NO NO NO JUST NOISE OR JUST THOSE IMPULSES YEAH CELP IS YEAH IT'S IT'S IT'S AROUND ONE KILO BYTE LIKE YEAH YEAH THAT'S A I THINK EVEN G. S. M. AND ALL THIS G. SEVEN TWO NINE YEAH YEAH ON BASED ON CELP AT LEAST IT GIVES BUT STILL THEY USE A CODE BOOK NO SO THAT'S REALLY UH IT'S MAYBE BETTER THAN LIKE USING JUST RANDOM NOISE OR YOU CAN USE LIKE UH A CODEC SIDED OR YOU COULD USE A SO THAT'S WHAT CELP IS DOING RIGHT SO YEAH SO THIS IS WHAT WE DO AND UH THAT MIGHT HELP A LOT OF COURSE BUT W YEAH EXACTLY THAT'S THAT'S THE QUESTION YOU'RE GONNA GET H LOT HIGHER BAND WIDTH AREN'T YOU I MEAN IT'S A HIGH BAND WIDTH STANDARD SO YEAH YEAH SO IF YOU TAKE A LOOK ON THAT SPECTRUM OF THAT OF THAT CARRIER SIGNAL WHICH IS MORE OR LESS LIKE THE COSINE IF YOU REALLY TAKE A LOOK ON THAT BUT IT IS KIND OF FREQUENCY SHIFTED COSINE OR FREQUENCY MODULATED COSINE RIGHT SO IT'S TH THE FREQUENCY STILL TO BE CHANGING OR OF COURSE THE AMPLITUDE IS JUST NOT CONSTANT ALL TIME IT SHOULD BE THEORETICALLY BUT PRACTICALLY IT'S NOT SO WHAT YOU CAN SEE FOR A ONE SECOND SIGNAL YOU M MORE OR LESS YOU ALREADY MIGHT SEE SOME LIKE ONE ONE UH IMPULSE THERE OR SPECTRAL LINE FOR BUT USUALLY THERE ARE MANY OTHERS WHICH ARE S QUITE SMALL BUT THEY ARE QUITE IMPORTANT IF YOU DON'T TRANSMIT THEM THEN THE SIGNAL IS QUITE ROBOTIC OR SOMETHING LIKE THAT SO IF YOU'RE REALLY TRANSMITTING JUST ONE SPECTRAL LINE BUT THIS IS WHAT YOU CAN DO AND YOU CAN UNDERSTAND PRETTY WELL THE SIGNAL IS AUDIBLE OR IF YOU'RE ADJUST UH TH FIND ONE ONE LINE ONE SPEAKER AND DOM DOM DOMINANT ONE IN THE SPECTRUM OF THAT C UH CARRIER HIL HILBERT CARRIER AND YOU JUST TRANSMIT THIS PARAMETER 'CAUSE IT'S A BIT TRICKY ISN'T IT THAT'S IT'S NOT LIKE A STANDARD I'M JUST THINKING I MEAN WHAT SORT OF OPT IT'S NOT LIKE YOU CAN'T JUST DO STANDARD UM YOU KNOW INVERSE FILTERING FOR UM SIGNAL RECONSTRUCTION OR ANYTHING LIKE THAT CAN YOU IT'S EVEN EASIER BECAUSE WHAT YOU HAVE TO DO IS JUST DIVIDE THE YOU JUST MULTIPLY THAT HILBERT ENVELOPE BY THE TABLE CARRIER THAT THAT'S ALL YEAH YEAH YEAH EXACTLY SO SO YOU JUST MULTIPLY THAT UH ONE HILBERT CARRIER WHICH IS TRANSCRIBED BY L. S. F. S BY THAT THIS ONE I. F. F. T. SIGNAL SO BUT THAT'S GONNA BE SUSCEPTIBLE TO HAVING PHASE PROBLEMS IS THAT WHEN YOU OR OUTPUT SIGNAL LIKE OF OF COURSE I TRY TO PLAY ALSO WITH THAT AND UH I FOUND THAT IT DOESN'T MATTER SO MUCH WHICH WHAT IS THE PHASE BECAUSE WE ARE USING JUST ONE SECOND WINDOW RIGHT