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  1. sundar_milo

    Need to design a filter to allow only voice frequencies

    A 4th order filter can do better in my project.First i shall design one and test it with different frequencies , plot the gain vs freq.
  2. sundar_milo

    Need to design a filter to allow only voice frequencies

    Thanks for sharing those info.i am planning to use an algorithm for correlation between predefined recorded signal and the input voice signal and if it is closer to 1 then that instruction is executed whatever it has been programmed for. Just like the dot product of two vectors a.b=1 if they...
  3. sundar_milo

    Need to design a filter to allow only voice frequencies

    Hi MP. I want to design a voice recognition system using TMS 320 C54X  DSP processor.To which im going to give the input voice signal through mic,amplifier and filter sections. First im concentrating in designing a good filter for this project.I dunno the attenuation and rejection values in dB...
  4. sundar_milo

    Need to design a filter to allow only voice frequencies

    Thanks for those replies.Now im confused with these two circuits given in the links you have posted.But i would like to go with the one that has a single supply version.According to the circuit given in the link provided  by Audioguru , it has to be fed with a dual supply(+15V and -15V).However...
  5. sundar_milo

    Need to design a filter to allow only voice frequencies

    Hi. I need a bandpass filter that should be able to allow only our voice frequencies and reject all other frequencies.I dont have any idea about the frequency range of voice but  i think that is not a problem at all.I searched for BPF in google and found this ...
  6. sundar_milo

    IR gate counter HELP!

    i also recommend you first create a pcb design using computer after making a scematic.and then u would have to print the board . for this design u need some pcb creator programs like express pcb,eagle layout editor. Eagle editor is the best one from user comments. but before everything we must...
  7. sundar_milo

    IR gate counter HELP!

    i think u would need the following components common anode 7 segment display - 3 IC 74160 - 3 IC 7447 - 3 IC 7485 - 3 IC 7400 - 1 Resistors 330 ohm - 21. I doubt that some more resistors are needed for grounding and other purposes. i think we need some others' help to do the resistors job. If...
  8. sundar_milo

    IR gate counter HELP!

    i dont know where you are from rybitski. but in dollars it would cost within 10 or 15 ithink(only the ic's).including others it might go upto $30 or so.
  9. sundar_milo

    IR gate counter HELP!

    hi im very sorry to post this late. :-[ just look at this pic and say what u think.
  10. sundar_milo

    IR gate counter HELP!

    Hey i have found a way to solve your problem of counting ,displaying in 3 digit display. It uses 3 IC 74160(counter), 3  IC 7485  (4-bit magnitude comparator ), 3 BCD to 7 segment display decoder(IC 7447) and an inverter (IC 7404). The circuit is somewhat complicated for me to draw but i will...
  11. sundar_milo

    IR gate counter HELP!

    i dont know about the schematic but i think u can find it in google.first tell us about the project you are upto.the ics i have mentioned are digital ICs .the link i have provided tells about the ics . http://www.kpsec.freeuk.com/components/74series.htm#7490
  12. sundar_milo

    Digital logic circuit design

    yes i was thinking about that too. what im asking is that the theory is feasible or not in your first look . Also im a little confused with the keyboard thing.is there any specific IC for doing keyboard job ? i thought of designing the keyboard myself and finally came to demultiplexers(1 input ...
  13. sundar_milo

    Digital logic circuit design

    Thx for ur advice audioguru. can u say something about my idea in that above picture showing a block diagram of my thoughts. regards sundar
  14. sundar_milo

    IR gate counter HELP!

    here are the pin diagrams. have a nice look
  15. sundar_milo

    IR gate counter HELP!

    Hi rybitski. i think i may have answers for some of your questions. the IC 7490 is a ripple counter,which u could use it for counting.IC 7447 is a BCD to 7 segment decoder. search for its pin diagram in this site or in google. regards sundar.
  16. sundar_milo

    Digital logic circuit design

    Hi again I've completed making the circuit as said by audioguru and it works PERFECTLY FINE .I also checked a NAND gate (7400) and it also works well.i used a 2 x 3v = 6v supply.i had some resistors with me,a 330 ohm and a 120,didnt use a 220 ohm but i will buy one and see the difference in...
  17. sundar_milo

    Digital logic circuit design

    Thx for ur replies audioguru. I was thinking to add a resistor between pin3 and the LED but i dont understand why u want me to add a 220 ohm between the pin2 and ground. I will test the circuit as u have said and i will tell the result tomorrow. Thank you very much. :)
  18. sundar_milo

    Digital logic circuit design

    Hi everyone. Im a new member of this great site.I hope this is the best place for me to improve my knowledge. Im also a newbie to this electronic world.I have a thought in my mind to design a walkie talkie like circuit .But in my idea i want to design a circuit that can send and receive text...
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