TEKTRONIX DA4084 needs special frame?

[Zero Cool]

Someone was telling me that because the TEKTRONIX DA4084 Distortion analyzer is a special military version that it can only be used with the special frame/rack it comes with. that you cannot put a SG505 signal generator in the same rack with it like you can do with the AA501 distortion analyzer.

Anyone familiar with the Tektronix distortion generators and the TM mainframe system enough to know what he is talking about??

[Murray Allen]

The mainframe supplied with the DA4084 is a crippled TM5003. It's missing the connector and components to allow another module to be plugged into the left hand slot.

You can either add the missing components to the DA4084 mainframe or get a standard TM5003/5006 mainfame with all slots enabled.

The DA4084 is a modified AA5001, a TM5000 series instrument controllable by GPIB. TM5000 series modules will only fit TM5000 mainframes.

The SG505 and AA501 are TM500 instruments with no GPIB. These will fit both TM500 and TM5000 mainframes.

[davygrvy]

the DA4084 has a SINAD test in place of IMD. SINAD is for testing RF receivers. Get an AA5001 instead or an AA501(A) for audio. Don't forget a low-distortion osc, too. The best is the SG5010 if you can find one.

[Murray Allen]

Originally Posted by davygrvy

the DA4084 has a SINAD test in place of IMD. SINAD is for testing RF receivers. Get an AA5001 instead or an AA501(A) for audio. Don't forget a low-distortion osc, too. The best is the SG5010 if you can find one.

While I agree that the AA501(A)/AA5001 is the more desireable analyzer, the DA4084 has the advantage of lower cost. For measurement of THD+N, noise, gain and level the DA4084 is every bit as competent as the others. I leave measurement of IMD to the spec-an.

Because of the low cost, I have modified several units to perform 20KHz audio bandpass and quasi peak noise measurements without fear of ruining an expensive instrument. I've also experimented with replacement of the input stage components to further reduce the noise floor.

It's also possible to run the DA4084 in certain TM500 mainframes by removal of a back-plane connector key. This avoids the switching noise created by the power supplies in TM5000 series mainframes.

The SG5010 is definitely a great piece feature wise, but the performance edge goes to the SG505 which has fewer output artifacts.

[Max Caliber]

Hello Zero Cool

The DA-4084 is a special distortion analyzer that was meant to tune radio receivers both for the military and commercial applications using the SINAD function, which replaced the IM distortion function on the AA-5001 analyzer.

My test setup uses the DA-4084 and the SG-505 (a very low distortion oscillator), housed in a TM-5006 rack along with two DM-501A meters (for stereo) and a FC-5009 counter. I never got the chance to test all of the functions on the DA-4084 nor was I ever able to connect a GPIB (IEEE488) computer to the DA-4084, who has such a computer now-a-days? However the manual and auto-tuning functions of the analyzer seem to work perfectly, I am always most impressed with this machine’s capabilities. I have over 40 years experience working with almost all the analyzers made (Bruel & Kjaer, Radford, Audio Precision, HP, Crown, etc) and I can say that the DA-4084 can sit among the best of the list.

One thing to note about the TM-5006 mainframe is that some of the plug-in positions are reserved for high power applications (scope, power supply, etc), however this slot can still be used for the DA-4084 without issues. Because the DA-4084 has a second rear card-edge connector, you cannot place this analyzer into a TM500 series rack, it has to be a TM5000 series.

When I originally purchased the unit it came housed in “a crippled TM-5003 cabinet” to quote Murry, and I had no trouble plugging the DA-4084 into my TM-5006 rack. I would have liked to have modified the TM-5003 rack so that it could have also housed the SG-505 oscillator, but unfortunately I could not find the proper connector to populate the back-plane.

Does anyone know where I could find a connector so that I can heal my crippled TM5003? And what (low cost) GPIB computer would be suitable for the TM-5006 / DA-4084 / FC-5009?

Philip

[davygrvy]

Originally Posted by Max Caliber

... And what (low cost) GPIB computer would be suitable for the TM-5006 / DA-4084 / FC-5009?

Search for a National Instruments NI-488 PCI card. Like this. You'll need the GPIB drivers for it for windows or use the open source drivers on Linux. Software that can talk to it could be something low-level such as this TCL extension and from there you script the communication or build stuff in LabView or LabWindows/CVI. There's probably Perl or Python extensions as well.

Don't kill yourself with those ancient GPIB computers, please.

[davygrvy]

Originally Posted by Murray Allen

The SG5010 is definitely a great piece feature wise, but the performance edge goes to the SG505 which has fewer output artifacts.

Note that you'll need two SG505s one with the WR option to do two tone IMD. The SG5010 already has it and I believe the ratios are adjustable programmatically, too.

[davygrvy]

Originally Posted by Murray Allen

It's also possible to run the DA4084 in certain TM500 mainframes by removal of a back-plane connector key. This avoids the switching noise created by the power supplies in TM5000 series mainframes.

Actually, I've found the 5000 frames to very quiet with regards to switching noise as Tek used the more expensive saturation design. Don't forget to also remove the whole GPIB/CPU board, too, as the GPIB edge connector will probably contact parts mounted on the 500 series backplane. I doubt that is possible.

Also beware of heat dissipation by the 5V regulator on the far right PCB inside the analyzer. The 8V supply on 5000 series frames is regulated, but not on 500 series ones, so it'll probably make more heat and there's not much forgiving with that one regulator as its running near the top of its dissipation already. Take a look.. its a heater.

I don't think its possible to put a DA4084 module in any standard 500 series frames.

[Zero Cool]

I use a AA501 at work and really fell in love with it. so easy to use. I have two Sg505's at work also one is the WR option. I hope to duplicate the setup in my shop.

I don't need the sinad obviously or the imd functions. I am mainly interested in the THD+N, noise, gain and level measurements. I just sold my HP339A but i need to save a few more pennies to be able to swing this.

[davygrvy]

Wait a sec... Is "Zero Cool" Dave M. from Minneapolis?

If so, Hey dude. The clues just seemed to fit.