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FeelTech FY6600 60MHz 2-Ch VCO Function Arbitrary Waveform Signal Generator
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GerryR:
The Spec sheet says the following:

"The true arbitrary waveform section generates point by point waveforms with lower jitter, high
resolution, and true representation of the required waveform."
"Due to the arbitrary waveform capability of the 4045B, the instrument is able to generate low-jitter square waves with greater edge
stability. The improved signal integrity allows these generators to be used for simulating reliable clock signals, generating triggers, or
validating serial data buses."

I haven't been inside it yet to see what is going on, but I don't see any jitter on through 20 MHZ, unlike the 6800, and the jitter I saw on the 6800 got really bad at the higher frequencies.  I may have gotten a poor unit, but it did have the 1.7.1 firmware.
bdunham7:
So to answer my own question, it appears the BK 4045B uses a 50MSa/s DDS for "general" AWG duty and a "True AWG" with a variable clock (probably up to 50 MHz) for the advertised low-jitter sine/square/triangle/ramp functions.  I might just "need" one.  BK Precision does have some nice stuff if you can get it cheap enough.  ;)

https://bkpmedia.s3.amazonaws.com/downloads/datasheets/en-us/4045B_datasheet.pdf

https://www.tegam.com/wp-content/uploads/2015/10/AN4011.pdf
 
bdunham7:

--- Quote from: GerryR on June 13, 2019, 01:08:55 am ---
I haven't been inside it yet to see what is going on, but I don't see any jitter on through 20 MHZ, unlike the 6800, and the jitter I saw on the 6800 got really bad at the higher frequencies.  I may have gotten a poor unit, but it did have the 1.7.1 firmware.

--- End quote ---

Were you looking at sine or square waves?  Square waves (and others) will have the jitter I described just because of the way DDS works, but on mine the sine waves are rock steady.
GerryR:
I'm talking about square waves; sine waves are clean, triangle waves show some distortion at higher amplitudes on the down slope(frequencies are fine).  I haven't done a full inspection of all it is supposed to do, but so far, it looks pretty clean.  I am going directly from the generator to the scope thru a 50 ohm terminator at the scope.  Oh, the DC offset, when set to "0," is about 1.35 mV, much better than the 35 mV of the 6800, which of course, there is a remedy for by some hacking.

At $125.00, you surely do need one!  ;D
vince53:
FM IF Sweep.

Getting this working was more about learning how my scope worked than my FY6800.
I produced these nice filled traces by using infinite persistence and adjusting the number of points.  I suspect other scopes may need to be adjusted differently.

First photo:  The purple trace is the generator output from channel #2, 1kHz sine wave with the amplitude at 6.2v and offset at 2.7v
Green trace: sweep of 10.2MHz to 11.2MHz using VCO mode with a cable from output #2 to VCO In at the back of the generator. 
Red trace:  FFT math function of green trace.

Second photo: Purple trace, input to VCO IN
Green trace: 1MHz wide sweep with the center at 10.7MHz.  The signal is fed through a Yaesu receiver prefilter.

Third photo: measurements for the control ramp.  DC coupling.  6.2v peak to peak, with 5.7 volts for the positive peak and and -0.57v for the negative peak.
The spec for the VCO In is 0-5vdc.  To get the full sweep I needed to start below 0vdc and ramp to about 5.3vdc.  This is consistent with an earlier post.  To get the full sweep I had to use 6.2v for the amplitude and 2.7v for the offset.  VCO IN maximum frequency is 500Hz but I had to go higher to get the trace on the scope.  Values may vary but it can be made to work.
1 Megohm input impedance of the scope was used. 

I couldn't figure out how to use the "Insert Image" tool so I'll try Attachments.

Vince KC8AAC
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