Recent content by JimmyAlz

  1. J

    Calculating a frequency offset using a PIC

    Did a quick google and found Microchips floating-point library for PIC16/17: http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en010961
  2. J

    How Can Transmission Lines Be Modeled and Matched?

    If you google AppCad you will find a free RF design package with calculators for different transmission lines.
  3. J

    Learning About Class A Amplifiers - Links & Resources Provided

    You might want to read what Rod Elliot has to say on the subject of Nelson Pass's ZEN Amplifier: (Is this what you are looking into?) http://sound.westhost.com/project36.htm
  4. J

    Proteus Professional, messing with my mind.

    Look at the voltages at the LED's. Some of them are negative; your simulation program can't handle this case. (In real life current would be very large and the diodes would catch fire)
  5. J

    Electrical Electron Accelerator/Decelerator grid supply

    Perhaps a thyratron tube would work better in this case? I am guessing they are expensive however. You will need some serious power to switch 1kV at 10MHz. Minimizing capacitances will be critical. Now that I think about it, how about a surplus high powered radio amplifier?
  6. J

    Build an IR Scope: A Detailed Guide to Zoomable Contrast

    The bolometer elements does not overheat because: 1) There is always some heat loss through conduction to the substrate. 2) There is always some heat loss through blackbody radiation to/from the sensor case. 3) When designing bolometer elements you *want* to have some heat loss, otherwise you...
  7. J

    Build an IR Scope: A Detailed Guide to Zoomable Contrast

    FLIR systems in the U.S. sells bare sensor chips and readout ASIC's. http://www.flir.com/cvs/cores/components/ I hear you :) That was the motivation for my thermal camera project as well. I'm about 60% done after 600+ hours of work. For a still image camera of 96x128 pixels. But I have...
  8. J

    What is the Best Voltage Regulator for a Dual Polarity Power Supply?

    I was a bit unclear ... you will need two regulators: one adjustable 0 to 35V and one fixed or adjustable set to +17V.
  9. J

    What is the Best Voltage Regulator for a Dual Polarity Power Supply?

    Easiest would be to generate a "fake" ground at +17V and then find a regulator that can do 0 to 35V. What I mean by that is that you should keep the power supply isolated from ground and then connect the case ground to the +17V output of your power supply. Search digikey.com (US) or farnell.com...
  10. J

    Build an IR Scope: A Detailed Guide to Zoomable Contrast

    I don't know of any book but I have some experience in this field. Just thought I should warn you: That sound like one of the most difficult projects you can get yourself into. You will need knowledge of the following: * DSP/Microcontroller programming * High performance analog amplifiers *...
  11. J

    Pull-up resistors w/ tracks for DDR2 SDRAM.

    Take a look at a PC mainboard that uses DDR2. The pull-ups are easy to find. Just use the same size as that manufacturer uses. Yes from what I understand length is critical. Again take a look at a PC mainboard, you will see many "wiggly" lines that adjust the lengths. I don't know about...
  12. J

    How to Create an Electrically Shielded Loop Antenna?

    Alright! Every day you learn something new :)
  13. J

    How to Create an Electrically Shielded Loop Antenna?

    If your antenna is shielded it will not work as an antenna.
  14. J

    PIC Code Uncertainty: Why Does Placement Matter?

    I'm confused, what do you mean by "(which is placed before the call)"? The placement of the code does not matter. this will work: org 0 ; or 0x0000 or 000h (all mean the same thing) goto start init <some code> retlw start call init main...
  15. J

    PIC Code Uncertainty: Why Does Placement Matter?

    Checked the data sheet ... 16F690 doesn't *have* stack overflow reset ... :/ So what happens is that the "retlw" instruction fetches an uninitialized value from the stack and jumps to it. So your code #2 works because you are "lucky". The uninitialized value just happens to point inside...
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