New product available: RF Explorer Signal Generator (RFE6GEN)

[Ariel Rocholl]

We are happy to welcome a new member to the RF Explorer family. The RF Explorer Signal Generator is a powerful, wideband fully programmable RF signal generator. It is the perfect companion for Spectrum Analyzer product line. As a standalone unit, RFE6Gen can generate CW and Sweep signals by selecting embedded menu options. When connected to a PC, it can be fully programmed with the RF Explorer for Windows software tool. Furthermore, the unit can work as a powerful Tracking Generator when used with RF Explorer Spectrum Analyzer connected to the same PC, offering full Scalar Network Analyzer (SNA) capabilities. The SNA feature allows full characterization of filters, amplifiers and any 2-port RF device. With excellent frequency and amplitude handling, it brings a truly affordable high performance, small form factor signal generator to the RF market. Download full datasheet specification here. For purchasing RFE6GEN, visit the SeeedStudio website or contact our worldwide distributor channel. Note: Hardware is final and fully calibrated, but RF Explorer for Windows Software and embedded Firmware are delivered BETA and under development. Please go to this reference page as well as our facebook page to get progress update and download new versions as released.

[GiorgioFoX]

Say hello to new Generator :)

[Wilhelm Ioachim]

Good news!

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[Ariel Rocholl]

New BETA software release with Tracking SNA functionality enabled. Instructions and details available at www.rf-explorer.com/rfgen

Some quick image demos attached:

• 1675MHz band pass filter
  

• Narrowband 130MHZ SAW filter
  

• Mini-Circuits SLP-550 low pass filter 550MHz
  

Results are inline with Agilent N9915A calibrated VNA.

[Ariel Rocholl]

New software version available with significant improvements in stability, GUI usability,  and some tracking sweep speed gain.

Download from rf-explorer.com/rfgen

We want explicitly to thank user Giorgio Campiotti for all his help in beta testing RF Explorer Signal Generator.

Regards,

Ariel

[Ariel Rocholl]

Updated version of the RF Explorer for Windows BETA with additional features and stability for Tracking SNA

BETA version 13 Oct 2014

This version improves stability and user experience, and increase tracking sweep speed a bit. This is the preferred version for all users to work with. This new version includes the following benefits:

• Stable auto-retry SNA normalization steps with internal averaging for more reliable data capture in noisy environments
• Average trace included with selectable count (recommended values between 3-10)
• Sweep frequency and power settings stored with named configuration settings
• User configurable title text graph added to behave the same as the spectrum analyzer graph
• Robust checks added to make harder introducing invalid frequency values beyond Signal Generator range and, if the spectrum analyzer is also connected, will limit the sweep & SNA frequency settings to that of the analyzer.
• Signal Generator settings are now visible disabled while the RF power is ON to avoid false expectation of the device following any GUI change after power is enabled.
• Informative real time text added for tracking mode including sample step scanning percentage
• Normalization data is now reset every time the configuration settings are changed to make it explicit the re-normalization step required. Otherwise the user may not realize the normalization data is no longer valid based on configuration change.

Please download latest software here: RFEGEN_Beta_13Oct2014.zip

More details at rf-explorer.com/rfgen

[Ibidapo Ilawole]

The RFE6GEN seems to be out of stock.

It is not available on Amazon and out of stock on the Seeeds store.

[Ariel Rocholl]

Hi Ibidapo,

Some of our distributors have units in stock. Please check here for Europe, here for Australia and here for Canada. Others may have too but these are safe bets.

A new batch will be in stock from Seeed and other distributors by early November.

Regards,

Ariel Rocholl
http://www.rf-explorer.com

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[Ariel Rocholl]

Thanks for your patience, a draft version of the RF Explorer Signal Generator is available at www.rf-explorer.com/RFGEN_manual

Feedback welcome, as usual.

Regards. Ariel

[Ariel Rocholl]

[BETA] New version of RF Explorer for Windows and Firmware

We fixed and enhanced several things, mostly of interest of users working with Tracking Generator SNA mode. Thanks all users who reported bugs and provided so useful feedback.

• [FIXED] Automatic and resilient detection of any USB combination. Prior to this fix, the application may confuse ports and not complete connection if the device was plugged on a different USB port in the computer than last time used.
• [FIXED] Typo in several message text and menus (thanks users Shaun O'Sullivan and Stewart Andreason)
• [FIXED] Sometimes SNA normalization or tracking could not start if frequency was right on module frequency boundary (e.g. starting right at 15MHz in a 3G Combo model may have not worked successfully in some cases)
• [Enhanced] Remote Screen tab is now available for Signal Generator too. In order to use it, the only device connected must be the Signal Generator, otherwise the Spectrum Analyzer takes precedence.

More information and software available at www.rf-explorer.com/rfgen

Regards

Ariel

[zfor...@yahoo.com.au]

Hi Ariel,

I was wondering does the RF signal generator need a termination load on the antenna socket when not in use to protect the circuitry (like the RF spectrum analyzer)?

Z

[Ariel Rocholl]

Short answer: That is always a good idea. I personally have my Signal Generator and Spectrum Analyzer protected with loads all the time, it is little investment and also helps to avoid any ESD risk.

Long answer: Note it is for a different reason than Spectrum Analyzer though. In the Spectrum  Analyzer case, you want it to protect against any strong external signal.

That won't be a problem for the Signal Generator because the output attenuator protects from very strong input signals, if that ever happens. However, the 50ohm termination does protect you against a mistake of turning the Signal Generator power to ON without a load.

Regards. Ariel

[tre...@gmail.com]

I loaded the new firmware from the 26 November Beta today and took a look at the output with my HP 8569B Spectrum Analyser. The result is shown below, at 6GHz. There are significant sidebands/spurious at plus/minus 4KHz and 8KHz (etc). Attenuator off, amplitude=3. At lower frequencies the problem is still evident, at 1GHz the sidebands are still only 45dB down. Changing the attenuator and level values don't seem to change the sidebands significantly. At I was hoping to be able to use the RF-gen as my "go-to" signal generator, but will need a cleaner signal than this. Has anybody any idea how I could clean the signal up a bit?

[tre...@gmail.com]

Two mistakes in my post above: first, the sidebands are offset by multiples of 4MHz, not KHz, and second, at 1GHz the sidebands have fallen to about -55dBm, but are still too high to be comfortable, IMO.

[Ariel Rocholl]

Hi - 

RF Explorer Signal Generator RFE6GEN is based on the MAX2870 sigma delta PLL. It certainly produce some spurs, but are state of the art when compared with normal fractional PLL. Check the MAX2870 datasheet to understand expected spurs and harmonics from this device. Note a measured -55dBc is a signal less than 100,000 lower power than the CW. It is certainly visible but may rarely impact any measurement. And these spurs and higher order harmonics have zero influence in the tracking SNA functionality as the software only tune reception at CW center frequency, as you may expect.

I would like to better understand your measurements. The graph says Span=2MHz so the spurs shown cannot be at multiple of 4MHz, they are apparently 400KHz.

Please check attached Agilent N9915A results with a 2MHz, 10MHz and 25MHz span at 1Ghz and 6GHz, using 10KHz RBW in all cases.

Regards

Ariel

[tre...@gmail.com]

Hi, The display shows 2MHz/ for span, which is HP talk for 2MHz per division. Amplitude is 10dB per division.

Well, I understand your focus on the RFgen being solely for use with the RFexplorer spectrum analyser - a 'tracking generator', in effect - but I suspect many others would, like me, assume that it was also useful as an RF generator, which is how you described it. The first image I have attached is from 0-2GHz with the RFgen producing a 0dBm 100MHz signal. While this 'picket fence' of harmonics might be acceptable from a tracking generator, it is hardly what I would expect from an RF Generator. The 19th harmonic, at 1.9Ghz, is still only approx 25dB down on the fundamental. There is no way this RF generator can be used with an SWR meter to tune an antenna, for example.

Second, I show the RFgen output at 1GHz, the spurious sidebands are at -55dBm. Finally, a photo at 100MHz shows the spurious signals at plus/minus 4MHz are definitely acceptable here. The frequency at which the spurious signals exceed - 60dB is 600MHz, and this represents a limit of utility for many RF generator applications.

Could you widen your sweep range and take a closer look at your own RF gen, please? Is it possible that the divider ratios might be chosen somehow to minimize these spurious sidebands?

Sincerely
Trevor

[Ariel Rocholl]

Hi Trevor,

Thanks for the clarification, 2MHz "span" language for the "division" was the missing part. 

Answering your question, yes the PLL can be programmed with different PFD and division ratios, some of them may reduce spurs, not for all frequencies of course but certain freedom exist. Still there is no a universal answer so we have plans to offer pre-selected modes that may help a lot with spurs, you will be able to select one of the available modes that may work best for a given frequency. This is still under research, note MAXIM offers no guarantee on spur levels so we are working on our own research to better characterize this over a large enough sample number. MAX2870 offer 3 modes, one expected to reduce phase noise, and 2 to reduce spurs, but the actual tests show no measurable difference. This is also the same kind of response we got with ADF4351 from AD. So the only way to actually change spur response is by experimenting with different PFD/division ratios.

Harmonics are certainly the biggest limitation for certain applications, this is the result of the squarish PLL output. There is no magic with PFD or division ratios that could help with that. Therefore we have an expansion module in the roadmap you could add to your RFE6GEN with a programmable LPF that will significantly reduce harmonics. We didn't add this in the baseline product as not everyone needs this filtering and so we can reduce cost in the base unit, adding extra features only if needed.

The RFE6GEN will not be suitable for direct feeding a SWR meter, not (only) because harmonics but also because 1mW (0dBm) output is not enough for what most VSWR meters need, which is typically in the range of 1-10W.

You can easily measure VSWR curve using the RFE6GEN  tracking generator feature and a directional coupler. We recommend ZHDC-10-63+.pdf from MiniCircuits for reasonable wideband support at a reasonable cost. This offer way more facilities than a SWR meter because you can picture the response vs frequency and see where the actual tuning is, and act accordingly, as opposed to a meter which needs constant try/error approach.

Regards,

Ariel

[tre...@gmail.com]

That MCL Directional Coupler is interesting. I have a stack of directional couplers that I use, each with a much lower frequency range. Below 1GHz, I use the MCL ADC-20-4. I have certainly spent more money on my collection than the cost of the ZHDC-10-63, however :)

I know that the Si570 also puts out a square wave with a pretty intense harmonic content, as I have built several VCO using them. But the RF6gen harmonic content, especially the even harmonics, seems to rise towards 1GHz, which I really didn't expect. It is interesting behavior from the MAX chipset. I was surprised that even though my calibrated HP detector (shottky diode) shows the RF6gen with 0dBm output, the harmonics distort that reading - the fundamental is actually below 0dBm on the spectrum analyzer. My citing a SWR meter was illustrative, and a bad example at that... But any sort of filtering would be welcome.

I haven't used the ADF4351, but there are several USB RF Generators on Ebay which seem to use it. One even publishes a phase noise  plot. I note one of the Ebay sellers is offering customized fixed filters. Certainly, if you make any breakthroughs in getting the amplitude of those 5GHz spurs down another 15dB or so, I would be very happy to beta-test that firmware :)

And thanks again for the RFexplorer, which fills an invaluable role in my toolkit.
 
Sincerely
Trevor

[Ariel Rocholl]

Thanks for your feedback - it is invaluable for us to know what features are more important so we can concentrate on them first. There are plenty of functionality that is pending and hopefully some of the upcoming developments may make a significant difference in the usability of the instruments for additional use-cases.

We expect to have major changes in the RFE6GEN firmware at some point in Q1, including the final implementation of sweep that is currently in progress.

I will add a note here whenever new beta firmware is available so you can test and help on tweaking the device for best results.

Regards

Ariel

[Ariel Rocholl]

RF Explorer Signal Generator - new firmware available

RF Explorer Signal Generator firmware upgrade v1.12 Beta 13 is available for download here.

It enables arbitrary Frequency Sweep functionality in the device (not yet avaialable in the Windows software) and several bug fixes and minor corrections. Details included in the firmware package.

This firmware and included Uploader tool can be upgraded in Windows and Linux. For details on firmware upgrade process use this link.

[Jay Thompson]

Got my generator today, just in time for class demos at IWCE, my fellow instructors are jealous.

I noticed that the start and stop freqs change after using the single freq CW button (in the PC program.)

Is there a way to disable the 'connect to a load' message from the PC?
I'm guessing you don't have a reflected power sensor to know if a load is on the port.

What about a time out timer?

When I did the firmware upgrade I did not see a prompt to turn the unit on after holding the left and right arrow buttons.

Will the software have access to step delay?

Will the software show the freqs as the unit transmits? Something like the analyzer sweep shows or maybe a bar graph like the wifi display on the analyzer.

[Ariel Rocholl]

Hi Jay,

Thanks for your feedback. 

Some of the issues you describe are resolved in latest firmware v1.12 Beta 13, please download from www.rf-explorer.com/download

See some additional answers below.

Regards. Ariel

On Thursday, March 12, 2015 at 3:12:04 AM UTC+1, Jay Thompson wrote:

Got my generator today, just in time for class demos at IWCE, my fellow instructors are jealous.

I noticed that the start and stop freqs change after using the single freq CW button (in the PC program.)

Is there a way to disable the 'connect to a load' message from the PC?
I'm guessing you don't have a reflected power sensor to know if a load is on the port.

Right, appropriate load is expected to be handled externally by the user, the device is blind in terms of reflection. In any case, the message could be done configurable, with a standard checkbox like "don't show this message again". 

What about a time out timer?

We can consider that as optional feature. What is the time range you think could be interesting to have? I do not see that feature in my bench grade generators, do you have a instrument model where this is being offered so we can better learn from it? 

When I did the firmware upgrade I did not see a prompt to turn the unit on after holding the left and right arrow buttons.

Will the software have access to step delay?

It does in the latest firmware. Or do you mind RF Explorer for Windows? It is not yet supported in Windows, but it will. 

Will the software show the freqs as the unit transmits? Something like the analyzer sweep shows or maybe a bar graph like the wifi display on the analyzer.

Yes, a more intuitive Signal Generator screen is on the works, including a bar graph when sweep is active. 

[Ariel Rocholl]

SNA how-to: Measuring Reflection - Return Loss

We are happy to introduce this new article/tutorial, specifically created for all RF Explorer SNA users.

Please check this article online: SNA how-to: Measuring Reflection - Return Loss

This image has been resized. Click this bar to view the full image. The original image is sized 1912x938.

Feedback & typos welcome, please provide details on the page itself or here, we will be adding a note with special notes later this week (e.g. to correctly understand the difference between standard directional coupler and special reflection bridge, etc)

[jay.thom...@gmail.com]

I'm running 01.12B13 from 2.24.15

>>with a standard checkbox like "don't show this message again". 

that would be great

>> I do not see that feature in my bench grade generators, do you have a instrument model where this is being offered so we can better learn from it? 

No I don't, I'm from the 2 way side of the business where we use time out timers on radios to prevent stuck mics, it's just a habit of worrying about the unit getting too warm from constant duty TX.

>>It does in the latest firmware. Or do you mind RF Explorer for Windows? It is not yet supported in Windows, but it will. 

yes, I'm using RF explorer for windows.

One more suggestion, can you but the release date next to the firmware or software version?

[RF Explorer]

You should probably ask this question in the MAXIM forums.

Regards

On Thursday, August 1, 2019 at 10:27:28 AM UTC+2, Mohsin Khan wrote:

I am using max2870evkit and when i try to increase frequency its singal level will low can you please tell me whether its regiter configuration issue or some max2870 fault or jumper that i am not attaching.