Author Topic: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator  (Read 40111 times)

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Offline BillyO

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #150 on: January 24, 2018, 11:19:04 am »
My JDS6600 60MHz arrived about a week ago.

I'm not sure how folks are measuring such huge mains leakage.  Mine measures ~1.2 volts AC RMS.  Not exactly what I'd call significant.  Perhaps it's the European/UK/Aus wall-wart or maybe your mains is not properly ground referenced.   In my house it behaves. :-//

I have read some other negative comments too, but wonder what folks are expecting for $125?

When I decided to purchase mine,  I did not expect it to compare favorably to a top of the line Keysight so I guess I'm not as disappointed as some of the folks here.  I'm not running an MIT research physics lab, just a retired hobbyist  working with vintage computers and sub-light speed microcontrollers.  It will surpass any needs I have. :-+

I do have one question for support though.  Is the firmware field upgradable?  Just in case you come out with new features I'll never need. :)

One thing I like about this over the FeelTech are the button keys.  They feel about 100 times better than the tacky membrane keys on the FeelTech. 
 

Offline hector.pascal

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #151 on: February 03, 2018, 09:02:36 pm »
Hi Trys,
Yes,I've been thinking of building a 5V linear supply for my JDS6600.
No problems with the 6600, but I am inherently suspicious of badly shielded "wall-wart" SMPS devices, especially around very low level wanted signals.   I appreciate that there must be at least one boost switching supply in the 6600 to get the output voltage swing, but those were obviously part of the overall design, and their spurious signals will have been carefully minimised to obtain the stated specs.
A 5V linear toroidal PSU isn't exactly rocket science, nevertheless I'd be very interested in your circuit, and any special precautions you added to prevent switch on/off transients, any over-current and over-voltage fault protection, and your choice of low noise regulator chip.  You can PM me if you prefer.
I guess, as usual in high tech R&D, the lowly mains connected PSU was a after-thought, and a convenient way of keeping the price low.  Nevertheless RDTech have done a very good job on this unit, and it annoys me how much criticism they get from people who nitpick comparing it to their professional test equipment costing $$$k.  When THEIR manufacturers can sell a similarly performing unit for the same price, I'll listen!
Regards
Hector
 

Offline TinkeringSteve

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Arbitrary Waveforms
« Reply #152 on: February 17, 2018, 03:12:45 am »
Hey,

As for Arbitrary Waveforms:
has anyone figured out whether it is somehow possible to use data from a *file* in the PC software, instead of drawing them by hand on that graph window?

If I right-click, there is an export in the context menu, but no import. And for that matter, it seems to use only screen coordinates.
How is one supposed to really use the full resolution of the 2048 points? (the drawing area has fewer pixels than 2048). It would be nice to input some data there that I generated.
 

Offline takfuji

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #153 on: February 17, 2018, 08:21:20 pm »
Steve,
Isn't there the key named "Open"?
 

Offline TinkeringSteve

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #154 on: February 17, 2018, 10:10:20 pm »
takfuji,

oh, yes, thanks.
LOL! I was fixated on the context menu for some reason, not seeing the forest for the trees, as it has a "export" entry.
 

Offline joeb8

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #155 on: February 20, 2018, 03:06:22 pm »
I can not find the trigger signal from the generator used for during a sweep generator function.
I have never heard of a generator that does the sweep function without the trigger / sync signal also being available to sync a scope.

thanx
 

Offline takfuji

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #156 on: February 22, 2018, 10:37:14 am »
Am frustrated, too. :(
My circumvention is to set the CH2 to exact same frequency and use it as the sync. I need to adjust the horizontal location on scope, though.
Tak
 

Offline Scratch.HTF

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #157 on: February 22, 2018, 08:28:33 pm »
Does the waveform have a lot of jitter at particular frequencies (e.g. 3/7/17/27/37/47/57 MHz) which means that the sampling rate cannot be changed?
If it runs on Linux, there is some hackability in it.
 

Offline 4x1md

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #158 on: February 24, 2018, 04:00:58 am »
A 5V linear toroidal PSU isn't exactly rocket science, nevertheless I'd be very interested in your circuit, and any special precautions you added to prevent switch on/off transients, any over-current and over-voltage fault protection, and your choice of low noise regulator chip.
Hi Trys,
I second Hector's wish and also would like to see your schematic.

Offline TinkeringSteve

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #159 on: February 26, 2018, 12:23:35 am »
Btw, what's with the NOISE function of this device?
I connected it to an audio amp, and what comes out is nothing like white noise, it's some sort of buzzing sound, and you can actually set its frequency.
What is that good for? (maybe I am wrong to expect white noise here, but that pitched sound is not something I'd have in mind when someone says "noise")

EDIT:
I see, it's not an FPGA function or anything but also just a fixed table for DDS, and if I set it to 1 Hz, it does resemble noise with not very much high end. I guess it would be somewhat more useful if it had a lot more points in each table than those meager 2K.
« Last Edit: February 26, 2018, 01:01:15 am by TinkeringSteve »
 

Offline emocabras

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #160 on: March 01, 2018, 05:33:41 am »
The JDS6600 generator family has very similar functionality to the Feeltech FY3200 and the MHS-5200 generators.  The JDS6600 even uses the exact same plastic case for the enclosure as the FY3200, MHS-5200.  For a comparison of those other generators see:
https://www.eevblog.com/forum/testgear/feeltech-fy3224s-24mhz-2-channel-dds-aw-function-signal-generator/msg697718/#msg697718

Huh, interesting. Thanks for the link!

Quote from: gby
From testing the FY3200 myself and reading on the MHS5200 they both are both limited in their output voltage range into 50 Ohm load without clipping or high distortion.  So the first test I would suggest is:

  1.  Set 10 KHz sinewave with 20 Vpp/maximum amplitude on an oscilloscope with 1 Meg impedance.  Then add the 50 Ohm termination and see if the output drops to 1/2 or if clipping or distortion starts happening.

1 meg impedance, max amplitude @ 10KHz:


50 Ohm termination:


Quote from: gby
On these type generators the output buffer is often slew rate limited which in turn means the output amplitude at higher frequencies is limited.  So, the second test I recommend is:

  2.  Set a 10 Vpp 100 kHz sinewave on the output into oscilloscope with 50 Ohm termination.  Then increase the frequency until maximum frequency to see if or at what frequency it starts distorting horribly.

So I think there are 2 interesting points here, at 10MHz and at 25MHz. Because above 10MHz the amplitude is restricted down from 20Vpp to 10Vpp (probably for slew rate reasons).

At the maximum frequency useable at 20Vpp (into 50 Ohms, so we should be seeing 10Vpp):



Looks pretty distorted. Here's an FFT (didn't use specan because I couldn't find my big attenuator :P)



So that second harmonic is at about -30dBc, which is out of spec (Spec says -40dBc).

At 25MHz, it looks a bit cleaner (but the amplitude is now 10Vpp out, which should look like 5Vpp into 50 Ohms):



And an FFT:



Looks to be about -40dBc, so that's roughly in spec.

Quote from: gby
On the FY3200 generator when you change the frequency the output waveform glitches.  Ideally one would expect a change in frequency with a sine wave to step change the slope at the frequency change with no step in the actual voltage.  Unfortunately the FY3200 has steps in the output because the phase as well as the frequency changes when you change the frequency.  So, the third test I would love to see is:

  3.  Set the generator to 5 Vpp, 10 kHz sine wave and then step change the frequency to 20 kHz.  Try to capture on the oscilloscope the moment when the frequency changes.  If you have advanced triggering I set trigger width must be < 20 uSec and then set to capture once.

Here's what that looks like:


Slightly zoomed in:


Quote from: gby
When you use two channels both outputting the same frequency sine wave with the phase 90 Deg apart it would be great to repeat test 3 to insure that both channels change frequency at the same time and with no glitches.

  4.  Repeat test 3 but with two sine wave channels outputting sine waves with 90 Deg relative phase.

I couldn't find a way to change the frequency of both channels at once, so I'm not sure if that's possible. Here's what 2 channels at 90 deg phase shift look like when channel 1 is increased in frequency:



Quote from: gby
The last requested test is really just a question of functionality.  This generator can do frequency sweeps.  But, can it do frequency sweeps while outputting two wave forms?  Last requested test is:

  5.  Can you set the generator to output 2 sine waves with 90 Deg relative phase and then sweep the frequency such that both channels sweep in frequency and stay in phase lock?

In advance I thank you for any of the above tests that you could do and report back results.

As far as I can tell it's not possible to do sweeps on 2 channels at once.

Cheers for your suggestions!

Hello

sorry; for your measurements did you eliminate the 50 ohm load inside the generator ?. if you have not modified generator your measurements 1 Mohm be really load 50ohm. when you write 50 ohms if you entered the 50 ohm resistor to be real 25 ohm load.

be, arrived one today to me, I have checked, the generator have an internal 50ohm load.

sorry for bad english i write from italy
« Last Edit: March 01, 2018, 07:39:20 am by emocabras »
 

Offline takfuji

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #161 on: March 01, 2018, 10:07:01 am »
>1 Mohm be really load 50ohm.

No.
Generator has 50ohm output impedance, which means series resistance.
vk2seb said "50 Ohm termination" and "into 50 Ohms", that means voltage get halved from the ogiginal DA output.  Electoronics 101.
Tak
 

Offline emocabras

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #162 on: March 01, 2018, 12:09:58 pm »
>1 Mohm be really load 50ohm.

No.
Generator has 50ohm output impedance, which means series resistance.
vk2seb said "50 Ohm termination" and "into 50 Ohms", that means voltage get halved from the ogiginal DA output.  Electoronics 101.
Tak

excuse me, I may have explained wrong, simply say that at the terminator the generator have 50ohm between output and gnd and create resistive divider.
I checked pcb, 56ohm be interposed between output and gnd of channels, r38 channel 2 and r57 channel 1.
with other generators do not have and to connect to my 1Mohm oscilloscope and I want to see correct amplitude I have to adjust to 50 ohm on oscilloscope input. I want to understand if eliminating 50 ohms it is possible to increase vpp of this generator.




« Last Edit: March 01, 2018, 12:13:46 pm by emocabras »
 

Offline takfuji

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #163 on: March 01, 2018, 07:41:28 pm »
>56ohm be interposed between output and gnd of channels
Did you check it when singal is present?
Those resisters are connected to BNC when signal is off, that means when the relay is turned OFF.
I just probed it and found no signal at either end of R38, nor R57, when signal is present at BNC.
Tak
« Last Edit: March 01, 2018, 09:21:14 pm by takfuji »
 

Offline 4x1md

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #164 on: March 03, 2018, 03:47:19 am »
Does anybody know where can one find details about the communication protocol of this generator?

Offline takfuji

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #165 on: March 03, 2018, 09:37:29 am »
>communication protocol of this generator?

On your CD, "\Chinese\JDS6600 Documentation\JDS6600 Communication Protocol.pdf".
Written in Chinese, though  :-\.
Tak
 

Offline 4x1md

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #166 on: March 03, 2018, 07:19:59 pm »
On your CD, "\Chinese\JDS6600 Documentation\JDS6600 Communication Protocol.pdf".
Written in Chinese, though  :-\.
It may sound strange, but there is no CD drive in my laptop.  :)

Offline GreyWoolfe

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #167 on: March 04, 2018, 12:49:02 am »
On your CD, "\Chinese\JDS6600 Documentation\JDS6600 Communication Protocol.pdf".
Written in Chinese, though  :-\.
It may sound strange, but there is no CD drive in my laptop.  :)

Not strange at all, my company laptop-a Lenovo T460 doesn't have one either.  I also have 2 gov't surplus computers without one.  USB DVD writers are cheap.
Why do people who know the least know it the loudest?
 

Offline tjones99

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #168 on: March 04, 2018, 04:57:19 am »
Here is the full text of the Chinese communication protocol document translated using Google translate... for what its worth...

Page 1
JDS6600 host computer communication protocol
? review
The overall control command using the command line, communication speed of 115200, issued by the PC
A command, the machine parses execution, and then returns the result to the PC. The following is a different order
Explain.
Send data format is as follows:
Start bit operator function number
Connector data field
End symbol
:
W
r
a
b
0-99
=
See instructions
Enter for the line


Description:
(1) The start bit is a colon (:) in the ASCII character table.
(2) The operator is one of the four lowercase characters in the ASCII character table, and "w" is the write
Command is used to set various parameters, "r" is a read command used to return parameters in the machine, "a"
The command is used to write arbitrary wave data. The "b" command is used to read arbitrary wave data.
(3) The function number is a numerical value in ASCII character table, and different values represent different parameters
Set.
(4) Data field: The data field is equivalent to the operand of the command, the number is 1 to 2048
A, each data between "," or "." To distinguish.
Such as: w23 = 25786,0.
 This instruction operand is 2, the first operand is
"25786", set the output frequency to 257.86, the second operand is "0" setting frequency
The unit of rate is Hz. In short, this instruction sets the frequency of channel 1 to 257.86 Hz.
________________________________________
Page 2
(5) Terminator: Each instruction is terminated with a carriage return + linefeed,
<CR> represents a carriage return in the ASCII character table (hexadecimal indicates 0x0d).
<LF> is a newline character in ASCII character table (0x0a in hexadecimal).
The following is the above two ways that carriage return line.
? W instruction
(1) waveform settings
For example: PC sends: w21 = 0.
 indicates that the waveform of channel 1 is sine
Wave, the machine returned OK indicates the setting is successful.
PC sends: w21 = 101.
 means that the channel output waveform is set to any
Italian wave 01, the machine returns OK to indicate the setting is successful.
PC sends w22 = 0.
 indicates the waveform of channel 2 is sinusoidal
Wave, the machine returned OK indicates the setting is successful.
The other waveforms are set as follows:
Channel 1
Waveform
Channel 2
: w21 = 0.

Sine wave
: w22 = 0.

: w21 = 1.

For the square wave
: w22 = 1.

: w21 = 2.

For the pulse wave
: w22 = 2.

: w21 = 3.

Triangle wave
And so on
: w21 = 4.

For the partial sine wave
: w21 = 5.

For the cmos wave
: w21 = 6.

For the DC level
________________________________________
Page 3
: w21 = 7.

For half wave
And so on
: w21 = 8.

For the full wave
: w21 = 9.

For the ladder wave
: w21 = 10.

For the anti-ladder wave
: w21 = 11.

For the noise wave
: w21 = 12.

For the index rose
: w21 = 13.

Exponential decline
: w21 = 14.

For multi-sonic
: w21 = 15.

Sinclair pulse
: w21 = 16.

Lorentz pulse
When: w21 = 101.
 means arbitrary wave
01 ,: w21 = 102.
 means Arbitrary Wave 02
And so on until a maximum of 160 means Arbitrary Wave 60.
(2) The frequency is set as follows
PC sends: w23 = 25786,1.
 Set the output frequency of channel 1 to
0.2586 unit is KHz, the machine returns OK means the setting is successful.
PC sends: w24 = 25786,3.
 Set the output frequency of channel 2 to
257.86 unit is mHz, the machine returns OK means the setting is successful.
Other cases are as follows;
Channel 1
Channel 2
: w23 = 25786,0.
 is set to 257.86Hz: w24 = 25786,0.

________________________________________
Page 4
: w23 = 25786,1.
 is set to 0.25786KHz: w24 = 25786,1.

: w23 = 25786,2.
 is set to 0.00025786MHz
And so on
: w23 = 25786,3.
 is set to 257.86mHz
: w23 = 25786,4.
 is set to 257.86uHz
(3) The amplitude is set as follows
PC sends: w25 = x.
 Set channel 1 amplitude output when x = 30
Is 0.03v, the machine returns OK to indicate the setting is successful.
PC sends: w26 = x.
 Sets channel 2 amplitude output when x = 30
Is 0.03v, the machine returns OK to indicate the setting is successful.
(4) Duty cycle settings are as follows
PC sends: w29 = x.
 Set channel 1 duty cycle when x = 500
Out of 50%, the machine returned OK that the setting was successful.
PC sends: w29 = x.
 Set channel 2 duty cycle when x = 500
Out of 50%, the machine returned OK that the setting was successful.
(5) Offset settings are as follows
PC sends: w27 = 9999.
 Set the bias output of channel 1 to 9.99v,
The machine returns OK to indicate that the setting is successful.
PC sends: w27 = 1000.
 Set the bias output of channel 1 to 0v,
The machine returns OK to indicate that the setting is successful.
PC sends: w27 = 1.
 Set the offset of channel 1 to -9.99v
The device returns OK to indicate that the setting is successful.
________________________________________
Page 5
When setting the bias output of channel 2, just change: w27 to: w28 to change the others.
For example: PC send: w28 = 1.
 Set the bias output of channel 2 as
-9.99v, the machine returns OK to indicate the setting is successful.
(6) The phase setting is as follows
PC sends: w31 = 100.
 means the phase output is 10 °, the machine returns
OK indicates the setting is successful.
PC sends: w31 = 360.
 indicates that the phase is 0 °, the machine returns OK means that the set
Set successfully.
(7) Tracking settings are as follows
PC sends: w54 = x, x, x, x, x.
 The value of the operand in the trace settings
(The value of x) is 1 or 0, 1 means that the synchronization 0 means asynchronous, and the synchronization is through
Road 1 for the operation object. The corresponding parameters for the number of operands are: w54 = frequency, waveform, amplitude,
Bias, duty cycle.
PC sends: w54 = 1,0,0,0,0.
 Set the frequency synchronization (waveform amplitude
Offset Duty Cycle Asynchronous), the machine returns OK to indicate that the setting is successful.
PC sends: w54 = 1,1,0,0,0.
 Set the frequency and waveform synchronization (amplitude
Degree Offset Asynchronous Duty Cycle), the machine returns OK to indicate that the setting is successful.
(8) Extended function (command write)
For example, the PC sends: w32 = x, x, x, x.
 where the operand value (x
Value) can only be 1 or 0)
________________________________________
Page 6
For example, PC sends: w32 = 0,0,0,0.
 means counting off Sweep amplitude modulation
Burst and start the measurement, the machine returns OK to indicate that the setting is successful.
If the PC sends: w32 = 1,0,0,0.
 Set the counter to start counting, the machine
Returning OK means the setting is successful.
If PC sends: w32 = 0,0,0,0. Said the counter is stopped. The machine returns OK
Set successfully.
Other cases are as follows
: w32 = 0,0,0,0.

Measurement starts (count sweep AM stops)
: w32 = 1,0,0,0.

Counting begins
: w32 = 0,1,0,0.

Sweep begins
: w32 = 1,0,1,1.

The pulse starts
: w32 = 1,0,0,1.

Burst begins
(9) function panel switch
If the PC sends:: w33 = 0.
 The machine panel will switch to the main panel and
Channel 1 is the main channel, the machine returned OK indicates the setting is successful.
If the PC sends:: w33 = 1.
 The machine panel will switch to the main panel and
Channel 2 is the main channel, the machine returns OK to indicate the successful setting.
Other cases are as follows
: w33 = 0.

Channel 1 is the main channel
: w33 = 1.

Channel 2 main channel
: w33 = 2.

SYS (system setting)
________________________________________
Page 7
: w33 = 4.

Measurement panel switching
: w33 = 5.

Count the panel to switch
: w33 = 6.

Channel 1 Swept panel
: w33 = 7.

Channel 2 sweep panel
: w33 = 8.

Pulse panel
: w33 = 9.

Burst panel
(10) Extended Functions (Measurement Functions)
If PC sends: w36 = 0.
 means the coupling is switched to AC, the machine returns
OK indicates the setting is successful.
If the PC sends: w38 = 0.
 means that the measurement mode is set to count frequency, the machine returns
Back to OK means the setting is successful.
Other cases are as follows
: w36 = 0.

Coupling AC
: w36 = 1.

Coupling DC
: w37 = 100.

Set the gate time for 1 second.
: w38 = 0.

Set the measurement mode (counting frequency)
: w38 = 1.

Set the measurement mode (meter cycle)
: w39 = 0.

Clear the count
________________________________________
Page 8
(11) Extended Functions (Burst)
Setting of pulse number
If PC sends: w49 = 5.
 The number of pulses is set to 5 and the machine returns OK
Indicates that the setting is successful.
Such as PC sending: w49 = 100.
 pulse number is set to 100, the machine back
Back to OK means the setting is successful.
Burst mode setting
PC send
Burst mode
: w50 = 0.

Trigger manually
: w50 = 1.

Burst for CH2
: w50 = 2.

For external burst (AC)
: w50 = 3.

For external burst (DC)
(12) Extended Functions (Sweep)
Start frequency setting
PC sends: w40 = 1000.
 Set the starting frequency to 10Hz, the machine
Returning OK means the setting is successful.
Set the stop frequency
PC sends: w41 = 1000.
 Set the termination frequency to 10Hz and the machine will go back
Back to OK means the setting is successful.
________________________________________
Page 9
Sweep time setting
PC sends: w42 = 10.
 set the sweep time to 1 second, the machine returns
OK indicates the setting is successful.
Sweep the direction
PC send
Sweep the direction
: w43 = 0.

normal
: w43 = 1.

Reverse
: w43 = 2.

round trip
Sweep mode
PC send
Sweep mode
: w44 = 0.

Sweep mode is linear
: w44 = 1.

Sweep mode is logarithmic
(12) Extended functions (pulse function)
Pulse width setting
PC sends: w45 = 1000,0.
 Set the pulse width to 1000 units as ns,
The machine returns OK to indicate that the setting is successful.
PC sends: w45 = 1000,1.
 Set the pulse width to 1000 units as us,
The machine returns OK to indicate that the setting is successful.
Cycle settings
PC sends: w46 = 1000,0.
 Set the period to 1000 units as ns,
The machine returns OK to indicate that the setting is successful.
________________________________________
Page 10
PC sends: w46 = 1000,1.
 Set the period to 1000 units us, machine
The device returns OK to indicate that the setting is successful.
Offset setting
PC sends: w47 = 100.
 Set the offset to 100% and the machine returns OK
Indicates that the setting is successful
Amplitude setting
PC sends: w46 = 500.
 Set the amplitude to 5.00 units V, the machine returns
Back to OK means the setting is successful
Recall and save
If the PC sends: w70 = 5.
 means that the parameters stored in the 5 position machine to return
Back to OK means the setting is successful.
If the PC sends: w71 = 5.
 means that the parameters in the 5 positions are retrieved
OK indicates the setting is successful.
If the PC sends: w72 = 5.
 means clearing the 5-position parameter
OK indicates the setting is successful.
? a, b instructions
a, b instructions are arbitrary wave writing and reading The following examples will be described in detail.
(1) Write arbitrary wave command (a command)
If the PC sends: a01 = 2048, 2048, ....... 2048.
 The machine returns
OK means that the waveform written in Arbitrary Wave 1 is DC level, and 2048 in the data field means vertical
________________________________________
Page 11
The coordinate value (y-axis) is 0, when the value is 4095, the ordinate value (y-axis) is 1, when
A value of 0 means that the ordinate value (y-axis) is -1 and the number of operands written in Arbitrary Waveform is 2048
Bit.
If the PC sends: a02 = 2048,2048, ....... 2048.
 The machine returns
OK means that the waveform written in Arbitrary Wave 2 is DC level.
If the PC sends: a03 = 2048, 2048, ....... 2048.
 The machine returns
OK means that the waveform written in Arbitrary Wave 3 is DC level. (Arbitrary wave maximum number is 60)
(2) Arbitrary wave read command (b instruction)
If the PC sends: b01 = 0.
 The machine returns the number of Arbitrary Waves 01
According to: b01 = 2048,
2048, ....... 2048.
 in its data section
The ordinate (y-axis) of the numerical expression is the same as above, and is not repeated here.
? R instruction
r command for the read command, the command format and write command format basically to one,
Do not repeat this description, the read command and the write command correspond to each other the following examples in detail
Description.
(1) The read command does not correspond to the write command as follows
If the PC sends: r80 = 0.
 The machine returns: r80 = 125. Said the current
The count is 125.
When in PC mode, the PC sends: r81 = 0.
 The machine is back
Return: r81 = 100000. It indicates that the frequency of the current measurement is 10000Hz.
When in PC cycle mode the PC sends: r82 = 0.
 The machine is back
Return: r81 = 100000. It indicates that the frequency of the current measurement is 10000Hz.
________________________________________
Page 12
Other cases are as follows
: r80 = 0.

Read the count value
: r81 = 0.

Read the measured value (in frequency mode)
: r82 = 0.

Read the measured value (in period mode)
: r83 = 0.

Read the positive pulse width
: r84 = 0.

Read the negative pulse width
: r85 = 0.

Read cycle
: r86 = 0.

Read duty cycle
When: r00 = 0.

Indicates to read the machine model.
When: r01 = 0.

Indicates to read the machine number.
(2) Read quickly as follows
PC sends: r81 = 4.
 The machine returns data from count value to negative pulse width.
PC sends: r81 = 5.
 The machine returns data from count value to period.
PC sends: r00 = 1.
 The machine also returns to read the machine model and serial number.
The read command corresponds to the write command as follows:
PC sends: r21 = 0.
 means read the current waveform of channel 1 if
Returns: r21 = 0. The current waveform is a sine wave, if it returns: r21 = 1. The current waveform is a square wave,
The other one and write instructions one by one correspondence in this not one by one.
PC sends when: r21 = 10.
 means reading the waveforms of channels 1 and 2 to phase
Bit of data.
PC sends as: r23 = 8.
 means read the frequency of channel 1 and 2 to phase
The data.
________________________________________
Page 13
The other read commands are not described here.

 

Offline tjones99

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #169 on: March 04, 2018, 05:22:36 am »
Reading through this thread as it is the best I have found so far. Thanks for all the info.

One thing I have not seen covered (hope I didn't miss it somewhere) is amplitude calibration.

I set the amplitude for 16V square wave (talking 25Hz here so no bandwidth issues) and I find I get 16.7v measured on the scope. First question everyone is going to ask is how do you know the scope is right? The scope was actually calibrated and I fed a second signal into the scope from a power supply that had a voltage of 8.02 volts (measured with an expensive calibrated HP DVM) and the JDS6600 output was higher than +8.02V. To get a true 8V peak output I had to set the JDS6600 to 15.3V amplitude.

I was hoping there was a mechanism to adjust (calibrate) the amplitude of the output.

There are 4 trim pots on the board... 1A 1D 2A 2D... anyone know what those accomplish before I mess something up really bad :-)

I looked through the communication protocol and saw nothing that I though helped.

Hoping RD Tech has some input on getting the amplitude closer to true!!

 

Offline Adrian_Arg.

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #170 on: March 04, 2018, 08:03:32 am »
This model of generator finings, which comes with external power supply, can be changed to a source of better quality, with a 15mhz I can use for hobby or should be higher Mhz. https://www.ebay.com/itm/JDS-6600-60MHz-Dual-channel-DDS-Function-Waveform-Signal-Generator-Counter-CE/372059704084?epid=2210616056&hash=item56a07c8b14:g:z2IAAOSwXGtZpMkois for use in small electronics projects
 

Offline Mr. Scram

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #171 on: March 04, 2018, 06:53:18 pm »
Reading through this thread as it is the best I have found so far. Thanks for all the info.

One thing I have not seen covered (hope I didn't miss it somewhere) is amplitude calibration.

I set the amplitude for 16V square wave (talking 25Hz here so no bandwidth issues) and I find I get 16.7v measured on the scope. First question everyone is going to ask is how do you know the scope is right? The scope was actually calibrated and I fed a second signal into the scope from a power supply that had a voltage of 8.02 volts (measured with an expensive calibrated HP DVM) and the JDS6600 output was higher than +8.02V. To get a true 8V peak output I had to set the JDS6600 to 15.3V amplitude.

I was hoping there was a mechanism to adjust (calibrate) the amplitude of the output.

There are 4 trim pots on the board... 1A 1D 2A 2D... anyone know what those accomplish before I mess something up really bad :-)

I looked through the communication protocol and saw nothing that I though helped.

Hoping RD Tech has some input on getting the amplitude closer to true!!
Is your lead properly terminated? At 25 Hz there shouldn't be any trouble anyway, but just to be sure. Youtube is full of people who claim defects or malfunction, while it's obviously operator error.
 

Offline Cliff Matthews

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Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #172 on: March 16, 2018, 10:52:13 pm »
RD Tech invents words.. As the box says, in their "lastest" video, some "unstruction" on software installation.
 

Offline bugi

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  • Hobbyist using the ultra slow and unsure method
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #173 on: March 26, 2018, 04:59:32 am »
I got mine earlier this week, and now have had time to test the JDS6600 a little bit.  I have no idea how old/new version it is. The box was "blank" (unlike some video/photos that I've seen which show text etc. on the box) and it felt like it had been stored in a swimming hall (and smelled like some chemical I have smelt perhaps once in couple years or so, just can't remember what chemical) :P   It was overall packaged pretty much watertight, so it must have been affected during storage - or maybe it is just different kind of chinese cardboard.

I collected any issues I've seen in this thread/topic or elsewhere, and went through them. I couldn't really test noise/quality stuff at this time, due to, hmm.., "mismanaging" some of my measurement cables (so the setup isn't the best), but most things are obvious even through less than optimal connections.

Note: I'm a newb, so some results (whether for better or worse) could be my mistakes. However, I did try my best to note earlier comments about how to test each case (and how not to test). When a case seemed to be ok, I tried higher frequencies than the typical 10k, just in case the issue is too short time to be noticed when looking at slower waveforms.

Overall, "good enough" for me, I just have to write a note about the channel 2 phase randomization quirk and tape it on top of the device, so that I don't forget it and waste hours some day later trying to figure out why my circuit is behaving badly, when it is actually the generator quirk doing it.


Results (with simple grade of OK/BAD/MEH):

(EDIT: "5V" etc. is amplitude, not peak-to-peak.)

1. Change frequency, waveform should remain continuous (no change in phase).
Sine 5V 10kHz to 20kHz and 5MHz to 10MHz, on single channel.

-> On channel 1, the phase continues smoothly.
BUT on channel 2, the phase makes a seemingly random change in the phase at the same time. (See also 2.)
Happens every time, not just occasionally.
OK / BAD.


2. Change frequency of one channel, unsynced, the other channel should not be affected in any way.
Sine 5V 10kHz to 20kHz and 5MHz to 10MHz (and relative phase 0 deg and 90 deg).

-> Changing the frequency of a channel results in the expected change in the output freq of that channel,
BUT channel 2 makes a seemingly random change in phase at the same time.
(Note, whether the adjusted channel is 1 or 2, channel 2 is the one that gets the weird shift in phase.)
Happens every time, not just occasionally.
BAD.


3. Change frequencies of both channels at once (synced); both should change simultaneously and phases should continue smoothly.
Sine 5V 10kHz to 20kHz and 5MHz to 10MHz.

-> Both channels change frequency and phases continue smoothly.
(Note how sync enabled prevents the phase shift issue on channel 2.)
OK.


4. Both channels, running long-term, should keep their relative phase and have no (unexpected) jitter/phase glitches.
Square and sine wave, 10kHz synced, 10MHz synced and unsynced, 8MHz and 4MHz unsynced. Using infinite persistence. With channels having the same frequency or at integer ratios in order to be easier to spot phase drifting.

-> No sign of glitches or phase drifting over long periods.
OK.


5. Sample rate and step size/resolution
5V and 2.5V 50%-50% triangle and sine, 10kHz, 1kHz, 100Hz and 10Hz. Zooming down to 10mV/div and timing to see the "steps" at positive zero-crossing edge.

-> Saw about 5mV per step for triangle, about 7.2mV/step for sine (both at 5V amplitude), and about 2.5mV/step for 2.5V amplitude triangle).
So, seems to be about 2000 steps per direction (half-waveform going up), or about 11-bits. Weird. Doesn't match directly with either the advertised 12-bit resolution, or the 2048 sample waveform length.
It looked like the negative side has slightly larger steps (triangle 5V, ~5.5mV on negative side vs. 5mV on positive side), at least near zero-crossing - perhaps "DAC" (the resistor-thingy) distortion?
Not quite what I expected (I somehow thought that for simple waveforms the on-the-fly phase calculation and RAM-LUT would be almost de facto at low frequencies (like the nice DDS-chips do, though with specialized circuitry), which would result in the full resolution being usable).
(More than good enough for my purposes; I can add extra filter on the output for lower frequencies if the steps cause trouble, though the possible distortions might not be as easy to handle.)
MEH.


6. Channels should be in phase accurately (simultaneously clocked output changes).
With sine and square, 10kHz 5V, same output for both channels, looking at rising edge.

-> Channel 2 seems to lead channel 1 about 2ns.
MEH.


7. Sync frequency sweep, the phase difference should remain constant.
Could not figure out how to check it accurately, so relied on "by the eye" and "waveforms overlap within pixel".
Checked both at low frequencies (<=10kHz) and higher (3-5MHz).

-> Seems to be ok, at least could not see similar relative phase drift as shown ealier in this topic.
OK.


I also took a look at noises and waveform shapes, but as mentioned, due to measurement setup issues, I can not be sure of the results. Of those, perhaps the most interesting results were
1. The difference in the shape of step-change ringing; channel 1 looked "normal", channel 2 was... weird..  Have to take another look at this later.
(Edit: tried with the leads that came with the generator; channel 1 ringing remained about the same, but the channel 2 weirdness turned to just "very very low ringing", so, seems likely it was/is just cable differences combined with generator output and/or scope AFE differences having fun with me.)
2. One channel ringing hard seems to leak to the other channel a bit. If this is by the generator (not by my bad setup), maybe tweaking it by adding a bit more capacitance and/or ferrite somewhere could isolate the channels better. Unless the coupling is in a shared amplifier or such.
« Last Edit: March 26, 2018, 08:17:28 am by bugi »
 

Offline Kimbo

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  • Posts: 1
  • Country: au
Re: RD JDS6600 25MHz 2-Channel DDS AW Function Signal Generator
« Reply #174 on: April 14, 2018, 11:53:42 am »
Thanks for the tips Takfuji.  30 dB is very useful!
Any chance of some photos showing how you implemented these suggestions?
 


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