Re: Waveform Generators - Any interest in BULK board / enclosure purchase ? ? ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Malcolm Watts <m.j.watts-at-massey.ac.nz> 

Hi Dan,
          I have a design similar in capability to that which you
describe. I didn't bother with uC for freq counting though - just
took a cheapskate approach and used a standard Intersil freq counting
chip and LED display (good for dark viewing and cheap to boot ;)

       The generator unbelievably goes to 12MHz before it runs out of
steam. One of the generator outputs is using paralleled current
buffer devices from NS (they are now obsolete unfortunately). They
also had a neat output for driving a LED to show when the output
stage was going to into current limiting (extremely useful for
knowing when the output impedance, set by suitably rated series
resistors is going astray). Together they can source 3A at several
volts with a minimum defined output impedance of 0.5 Ohms.

       However, the point of this message was to note and suggest the
following - I have found that the sinusoidal output of the 038 is not
as symmetrical as one would hope and there is a clear switching
artifact present at the sinusoidal peaks, a reflection no doubt of
the switching action of the comparator. My approach for a new
generator would be to use a DDS chip. Not that I am going to do it in
a hurry - being aware of the limitations of my present generator
means knowing when some results are being skewed in audio
applications and the generator does work very well, especially for
coiling measurements. A fine tune control is a must for Q
measurements and the like.

Malcolm

On 3 May 2004, at 8:18, Tesla list wrote:

 > Original poster: "Eastern Voltage Research Corporation"
 > <dhmccauley-at-easternvoltageresearch-dot-com>
 >
 > Actually Gary, you are right on board.
 > I was thinking of marketing something like that, although I didn't
 > realize that Terry already had a similar design.
 >
 > I was thinking of designing a unit that could:
 >
 > A.  Measure inductance
 > B.  Count Frequency
 > C.  Waveform Generator
 > D.  Tuning Indicator (sensing voltage or current)
 >
 > It would all mostly be PIC based (yes, I have written PIC code for a
 > nice inductance meter before) except the waveform generator would
 > probably be based on something like the MAX038 waveform chip.
 >
 > Hmm . . . .
 >
 > Dan
 >
 >
 >