Build your own Test Equipment !!!

[Eugene52]

Build your own Test Equipment !!!

I found out that you can still purchase plenty of MAX038's and I sure like this circuit I found today !!!....... Yes , the AD9833 is a superior or better chip , but the external circuits I found for it are much more complex and software is required . I think Maxim is stupid to discontinue the MAX038 chip........Here is one of the D.I.Y. "do it yourself " signal generator circuits I found , the pdf schematic and the Authors prototype photo . I will post more generator circuits using both the MAX038 and ones using the AD9833.........Regards..............Eugene

[Eugene52]

A clean signal Generator for noise tests.....

Thank-You Carl , KingJL . The price of the AD9833 is around $6.00 us dollars , not bad at all , because the signal to noise and THD specs are better than excellent !!! Now I am searching the internet for external signal generator circuits for the AD9833.............Thanks.................Eugene

[KingJL]

Eugene,
Check out the AD9833.
Regards,
J. L. King

[Eugene52]

A Clean Signal Generator for noise tests.....

MAX038 was obsoleted because they shut down the fab that made them. For a fantastic sig gen look at Analog Devices DDS chips.

- Carl

Carl , Thank-You !! Bad news turns to good news !!! Analog Devices might be a better product and maybe they have a better price !!! I will check it out asap...............Regards................Eugene

[Carl-NC]

MAX038 was obsoleted because they shut down the fab that made them. For a fantastic sig gen look at Analog Devices DDS chips.

- Carl

[Eugene52]

A Clean Signal Generator for noise Tests

I found this Great information Today !!! Just wondering if anyone has bought and used a Max038 I.C. chip for signal generation circuits . I found 2 circuit schematics that run from about 1 khz to 20 mhz . Actually I would only need a 1 to 100 khz generator , a TTL , sine , square or triangle waveform can be generated on the circuits I found . I am just trying to find the cheapest price. I want a signal generator that will have 2 outputs . And this will be a great test device for Golden Sabre Light noise problems using a dual trace oscilloscope and 1 channel of generator used at front end of golden sabre and the other to the input channel 2 of oscilloscope and the RX output to channel 1 of oscilloscope. I know this can be done , and plus I need a good signal generator anyway !!!............. Thanks...........Eugene

[ta2ctp]

Many Quality Measurement Devices..

Hi,
The following link has been very good measurement devices.
LİNK : http://cappels.org/dproj/Home.htm

Best Regards
ta2ctp

[Aziz]

Cool stuff!
http://www.youtube.com/watch?v=s1eNjUgaB-g&e

[Fred]

The best oscilloscope project i have seen so far.
http://www.semifluid.com/?p=15
Regards,
Fred.

[Aziz]

Last days, I measured the coil inductance with some environmental noise. The parallel LC resonant circuit is amplifiying on its resonant frequency everything induced in the coil, even noise. So this can be seen on a spectrum analyzer. It is not accurate enogh, but good for its simplicity.

The laptop MD will have some measurement instruments built-in:
- Scope (time-domain)
- Spectrum analyzer (frequency-domain)
- Lock-in amplifier (for other purposes than metal detecting)
- LC meter (for coils)
- Milli-Ohm meter (for coils)


Aziz

[gwzd]

Hi gwzd,
That looks interesting, that way curves for diodes and transitors could be traced.The only problem is that the ´242 is a bit more dificult to find now and expensive.

I never write absolute code, only relocatable one. So, adapting that for any of the 18 series would be no problem at all. By the way, I didn't know it was getting hard to get the '242.

It´s similar with the F84 ...
Here goes a signal generator,well designed ,but in French.No much to read anyway.
Regards,
Fred.

Did you know that Maxim is no longer manufacturing the MAX038? Then again there must be thousands of those chips around. I was playing around for a couple of weeks ago with some of the linear I2C and SPI controlled oscillators. Have a look at the LTC6904 for instance, it goes from 1kHz up to 68MHz in one go. The beauty of it is that it is very accurate, from the beginning I didn't believe much their claims about 1% frequency accuracy, but I must admit they were merely claiming a fact.
Regards,

[Fred]

. I don't know if you have encountered this or not but when balancing bridges specially at a few hundreds MHz it is important to have matched diodes. Regards,

Ok i undertand now.so you build you own mixers? cool !.
Yes measuring only the capacity at a single voltage won´t tell you about real linearity matching...
regards,
Fred.

[gwzd]

No Fred, you misunderstood me. It is not a curve tracer for diodes, what it measures is the capacitance of the diode depending on the applied voltage. I don't know if you have encountered this or not but when balancing bridges specially at a few hundreds MHz it is important to have matched diodes. You can, of course, buy them already matched, but you can do the work yourself by testing the capacitance, the forward voltage and the reverse leakage. A curve tracer should not be any problem to build, I have an old, from the eighties, Tektronix curve tracer and have never had the need for another one. That could be an interesting Saturday afternoon project.
Regards,

[Fred]

Hi gwzd,
That looks interesting, that way curves for diodes and transitors could be traced.The only problem is that the ´242 is a bit more dificult to find now and expensive.It´s similar with the F84 ...
Here goes a signal generator,well designed ,but in French.No much to read anyway.
Regards,
Fred.

[gwzd]

Hi Fred,
Very interesting, I haven't seen before the version using the '628 comparators.

I made one based on the '242 a few years ago and used a LM311 for the main oscillator. I chose the 18 series because of the hardware multiply, and of course because I had a couple of chips lying around. The interesting thing was putting a digital potentiometer from Catalyst and measuring the capacitance of diodes as a function of the voltage, everything sent via RS232 to the PC and viewed with a very primitive VB6 software. I'll check around to see if I can find the code, I know where the schematics are.

I think Eugene has started a terrific thread!

Regards,