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Everything posted by Shahriar

  1. ;D ;D Yeah, I am Going to build it. ;D Although I didn't understand anything, but I thank Audioguru, it is very good for a start! Shahriar
  2. Hi Imagine you want to build a Laboatory System which has a common Shield cable through all Sets.The system should have the capability of talking persons to each other seperately. I mean in the following System with 4 Sets, Person No.1 wants to talk to No.3 and No.4 Wants to talk to No.2 without Interfering their sounds. how is this possible? My plan is Mic Amplifier No.1 & No.3 should Modulate their signal in a seperate Frequency (i.e. 1Mhz) and the same for No.2 & No.4 (i.e. 1.1Mhz) ThanX Shahriar
  3. Dear AudioGuru Go to this project in Project section. "Amplifier 2x30W with STK465 " at the bottom of the schematic I have attached, in 8th line, it is written: "Finally, at the same time with the exit exists networking RC (0,1mF - 4,7 Ohm) that it attends to the minimisation of phenomenon crossover. " ThanX again Shahriar
  4. Dear Yogi ThanK you for you reply. I have found an IC "PDIUSBD12". I have not tested it yet, but it sounds good ThanX Shahriar
  5. Dear Audioguru On a circuit explanation, I remeber that was written that the 10 Ohm resistor and the cap are to decrease Cross over Phenomena!!! I don't know how? Does the resistor and cap play any roll in Cross Over either? ThanX Shahriar
  6. Thank you very much. Don't you know that if experts can overcome this problem by Digital Sound processing Tricks? To examin this I conected my Mic to my Sound Card and then Increase the Speaker Volume. The same thing happened to it too. But I am Not sure if my Sound card is Based On Digital Sound Processing.... ::) By the Way, Does Omni directional Microphones Solve this Problem? Shahriar
  7. Hi In My area there is a Chinese device that has a RF (TUNER) Input and a VGA Output and you can Convert your minitor to TV, It has also an RCA Input. It's name is Combo-TV. It is not very expensive in my area about 18$. HTH - SHahriar
  8. Hi I have built a PreAmplifier and a Power-Amplifier and it works Very good when I coonect my PC output to it. When I connect My Electric Mic to it and Increase the volume, a Sound Like a horn appears On the Loud speaker.This also happen when mic is Close to LoudSpeaker. Let me tell My Oponion about the reason and you tell me if I think right or not. The Mic take a harmonic and this Harmonic will be apmlified by PreAmp and PA. When This harmonic comes out of the Loud Speaker the Mic takes it again and the cycle Begins oNce more so an Oscillation occures and we hear that like a horn Sound. What should we do to solve this problem? ThanX in Advance Shahriar
  9. Yeah, That's it! ;D Thank you very much Shahriar
  10. Dear gogo Thank you for your reply! I asked the same question from a FPGA Expert that I found his email in his website http://www.fpga4fun.com This is what he asnwered: Use a MCU when you need to do something once in a while, use an FPGA when you must do something continuously. For example, doing an Ethernet packet analyzer can be done with a MCU, since you receive packets once in a while. But doing the Ethernet physical receiver needs to be done in hardware (FPGA), since the receiver is actually the piece of hardware that continuously listens to the wires to see if a packet is coming. Hope that's (kind of) clear. Jean
  11. Hi When I go to market, I see some modern TVs which is written on them: " 100Hz Scan " My question is when the Transmitter sends 50 Pictures per second, then How they show 100 Picture per second? ThanX Shahriar
  12. No, Building a good one for customers is impossible for me! I bought one which was made in Taiwan with a SAW filter and lots of SMD Components! HTH - Shahriar
  13. Hi, My question is: when should the project use a microcontroller, or when should it uses FPGA? Can you provide a good example of the project. The project that comes to my mind are: a. A pong game using LCD interface and push buttons. b. A stepper motor controller that will control 2-3 motors c. A simple version of Atari game console d. An oscilloscope e. A project that involve image processing from camera input At first I thought that from a hobbiest, that they will make it in microcontroller but in industry they will do it using FPGA. But after further thought, since the cost of FPGA is more that a simple microcontroller, this is not making sense. Thank you, Shahriar
  14. Hi Does anybody know How is it possible to send some data to PC via USB Port Using an AVR MCU. I think this is the problem of so many people. ThanX in advance Shahriar
  15. ThanX a lot So I am going to test both of them, First I will use two upto Isolator to connect the Serial Port pins to my device and then try a 600 ohm transformer. ThanX again Shahriar
  16. Hi I have built a device which shows Caller ID on PC via Serial port. that works properly, but the problem is that when as soon as I connect the serial port to my device a Vizz(bad sound) apears on telephone. the serial port has the same GND with telephone line and other pins of serial port goes directly to RS232 IC. What is the reference of this Parasit and how can i Solve it! Thanks in advance Shahriar
  17. Oh sorry, I meant Ante, I mis spelled it with Alun
  18. Dear 2old4digital You Mean If I touch ONE(?) Pin of a fully charged Capacitor {charged with more than 100 Volts} then It gives me a shock? ??? ??? ThanX Shahriar
  19. Dear Alun It is a 150Ah Battery, Can you tell me how much current do I need to charge it, and what kind of Power supply I need to Charge this battery? ThanX in advance Shahriar
  20. Hi In a TV, in its Isolated Sectin (Cold Chasis), when You touch 130V line, it gives you a Shock? How electricity close its circuit? This happen seriously with High voltage pins in deflection section too. Can anybody say why? ThanX Shahriar
  21. Hi I have a Triac, "BT136" when I connect the T1 and T2 Pins to AC voltage, I can turn it off and On with giving a DC voltage to Gate Pin, but when I try to Turn On and Off a DC load, the triac Doesn't turn Off? it remains On, till I disconnect the power! Shold I trigger the gate with a negative pulse to turn it off? If so, How? ThanX Shahriar
  22. Dear indulis I know that LM317 can not Handle 15A. I send that schematic to show how my circuit is going to charge that battery. INSTEAD OF that LM317, I want to use a PC ATX Power supply. Just to limit the current I want to pull Up the stand By pin PC Power supply. The Only thing I want to know is That: "" Is it possible to limit current at 15A By pulling up the Stand By Pin Of an ATX Power Supply, Or that ATX will turn on and Off repeatedly??? "" Sorry to say this, But I am writing the same sentences as I have written in my previous Post.... ??? ??? ??? ThanX Shahriar
  23. In TV reapiring, there are some problems that will beOkay a few minutes after the TV works. i.e. there is no Ruster,, {after few minutes, it appears.} it is alwasy beacuse of an Electrolit Cap. Bad Caps when get hot start working properly, but when they are cold, Some of their specifications Differs... I should say that this happen mostly in those caps that get charge and discharge repeatedly HTH - Shahriar
  24. Yeah It is the best what Ante Said, because dealing with an ATX Power supply wihtout a Schematic is really Disgusting.... Shahriar
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