Great to have the Avermetrics people here, and welcome to Paul. It give me better confidence in your products that I can communicate with the right people....
As you probably know, there is the new audio analyzer from JensH / RTX, which seems to be a fine piece of equipment, but from my point of view it's lacking the digital interfaces and have to rely on 3rd party software, and none of them are great, have already tried most of them and they all have issues....
I was looking to get a used AP or DScope, or even doing my own, but then the AverLab came along.... I like that you use ethernet for the computer interface and do your own software, even as you risk a little buggy first release....
It open up the possibility of using much higher sample rates, you really should put priority doing the ADC part using one of the faster Linear Technology chips, then you can look at aliasing spectras, class-D noise and other stuff you normally would need another piece of equipment for.... If the ADC part of the AverLab is a module it would be easy....
Please put priority for THD only measurements, an important feature for me
.
It would be good to have just one step higher voltage input, but it's not a problem with power amplifiers, no big deal to have a divided output from your dummy load....
Please let me know when you ship, I would like to purchase one.
As you probably know, there is the new audio analyzer from JensH / RTX, which seems to be a fine piece of equipment, but from my point of view it's lacking the digital interfaces and have to rely on 3rd party software, and none of them are great, have already tried most of them and they all have issues....
I was looking to get a used AP or DScope, or even doing my own, but then the AverLab came along.... I like that you use ethernet for the computer interface and do your own software, even as you risk a little buggy first release....
It open up the possibility of using much higher sample rates, you really should put priority doing the ADC part using one of the faster Linear Technology chips, then you can look at aliasing spectras, class-D noise and other stuff you normally would need another piece of equipment for.... If the ADC part of the AverLab is a module it would be easy....
Please put priority for THD only measurements, an important feature for me
.
It would be good to have just one step higher voltage input, but it's not a problem with power amplifiers, no big deal to have a divided output from your dummy load....
Please let me know when you ship, I would like to purchase one.
Hi Udo,
The short answer is: yes. AverLAB has word clock in and out via BNC's on the back panel, so you can use an external word clock signal to synchronize the digital PLL. Of course, you can also use the embedded clock that is in all the digital audio data formats by setting the sync source to the input of interest.
Note that the PLL is only on the digital audio side. The analog generator and analyzer have a separate (actually two separate) clock generators that are independent from the digital PLL--thus dual domain operation.
I'm not sure I understand you question about clock distribution between modules. Do you mean are we able to distribute clocks to external AverLine modules in an expanded AverLAB system? In that case, if the same clock domain is needed across more digital interfaces you would distribute word clock, sourced from AverLAB, to the WC inputs on the other modules. Using that technique you can create digital audio test sets with insanely large channel counts, all running off the same domain.
You correctly point out that very low jitter is necessary to get the kind of jitter performance it takes for these sort of THD and SNR results we do. For the PLL, we use a custom version of the JetPLL, with a low phase-noise RF LC VCO, and see numbers on the order of 16ps or so in a 40kHz bandwidth. This is a hybrid analog/digital PLL that is quite complex. But there is at least one PLL IC from Cirrus that does something similar, but I've never used it and I'm not sure it can drive an external LC oscillator. (Typical all-silicon solutions use ring oscillators, which are cheap, and not bad, but can't get close to an LC oscillator for phase-noise/jitter performance.)
Paul
The short answer is: yes. AverLAB has word clock in and out via BNC's on the back panel, so you can use an external word clock signal to synchronize the digital PLL. Of course, you can also use the embedded clock that is in all the digital audio data formats by setting the sync source to the input of interest.
Note that the PLL is only on the digital audio side. The analog generator and analyzer have a separate (actually two separate) clock generators that are independent from the digital PLL--thus dual domain operation.
I'm not sure I understand you question about clock distribution between modules. Do you mean are we able to distribute clocks to external AverLine modules in an expanded AverLAB system? In that case, if the same clock domain is needed across more digital interfaces you would distribute word clock, sourced from AverLAB, to the WC inputs on the other modules. Using that technique you can create digital audio test sets with insanely large channel counts, all running off the same domain.
You correctly point out that very low jitter is necessary to get the kind of jitter performance it takes for these sort of THD and SNR results we do. For the PLL, we use a custom version of the JetPLL, with a low phase-noise RF LC VCO, and see numbers on the order of 16ps or so in a 40kHz bandwidth. This is a hybrid analog/digital PLL that is quite complex. But there is at least one PLL IC from Cirrus that does something similar, but I've never used it and I'm not sure it can drive an external LC oscillator. (Typical all-silicon solutions use ring oscillators, which are cheap, and not bad, but can't get close to an LC oscillator for phase-noise/jitter performance.)
Paul
Hi Soren,
At this time the hardware for AverLAB is complete. AverLine modules are controllable by AverLAB and we do have plans for new ones. How much bandwidth do you need for your work?
We already have a feature request in the system for a THD only (no +N) measurement but I doubt we will have time to get this into the initial release. The ability to factor in the use of an external attenuator is a high priority for us. If it doesn't make it into the first release, it will be added shortly thereafter.
At this time the hardware for AverLAB is complete. AverLine modules are controllable by AverLAB and we do have plans for new ones. How much bandwidth do you need for your work?
We already have a feature request in the system for a THD only (no +N) measurement but I doubt we will have time to get this into the initial release. The ability to factor in the use of an external attenuator is a high priority for us. If it doesn't make it into the first release, it will be added shortly thereafter.
AP have an option for 1 Mhz bandwidth for some of their models, that would be fine with me.... Just take the 15 Msps LTC2387-18 and decimate a little....
Yes, AP's BW-52 option is nice. Unfortunately, an analyzer with that option costs over $16K USD if I recall correctly. There is no technical reason why we couldn't create an AverLine module with similar functionality. The order of new module development is a business decision though. While I suspect we will always have some overlap with AP, we also plan to break ground in new areas. Right now our energies are focused on releasing AverLAB.
Hi Ruairi,
We're actually in Eagle Rock, so we might be closer than you think!
The way the app is designed, things like tests are basically modules (I love modules, as you can tell.) So IMD will be coming quickly. Multitone tests are in the queue as well, but will likely take a little longer. We have an oscillator that can generate a large number of tones at once, but it's not in the current codebase so there's a little extra work to tackle on that front.
Paul
We're actually in Eagle Rock, so we might be closer than you think!
The way the app is designed, things like tests are basically modules (I love modules, as you can tell.) So IMD will be coming quickly. Multitone tests are in the queue as well, but will likely take a little longer. We have an oscillator that can generate a large number of tones at once, but it's not in the current codebase so there's a little extra work to tackle on that front.
Paul
Linkwitze’s 5-cycle burst? Cosine Burst
Useful for electronics and speakers. A period based (time axis) waterfall plot of the results is very revealing.
dave
In all my time at AP, I only knew one customer to use a cosine burst but he had some pretty good reasons for using it. AP only had one model that provided this and it was discontinued about 7 years ago. Their perspective was that the cosine burst was just a lower bandwidth alternative to a square burst so it was never offered again. Of course, that was a somewhat myopic opinion.
As Paul mentioned earlier, the modular design of our software will make adding tests simpler down the road. We still have work to do adding more common measurements like IMD but I have noted your request and will do some research on the Linkwitz usage. Maybe I will be able to corner Linkwitz himself for a few minutes at the AES conference next week.
As Paul mentioned earlier, the modular design of our software will make adding tests simpler down the road. We still have work to do adding more common measurements like IMD but I have noted your request and will do some research on the Linkwitz usage. Maybe I will be able to corner Linkwitz himself for a few minutes at the AES conference next week.
These are important point, hardware as well as software. You probably want to attract the people that cannot afford an AP or dScope, but want something better than a good soundcard and say ARTA.
So you probably should articulate what additional possibilities and/or performance the Aver brings to the table for the extra money.
Jan
So you probably should articulate what additional possibilities and/or performance the Aver brings to the table for the extra money.
Jan
Hi Jan, There are some very good soundcard solutions out there. Most are focused on acoustical measurements so the voltage limitations of soundcards are not an issue. Very few of these solutions support digital audio (or maybe I have just never seen them used for digital audio). I am also not aware of any soundcard solutions that support test automation, calibration, networked usage and Mac/PC cross platform compatibility. These are things that are more likely going to be of value to a small business rather than a hobbyist.
BTW, I was told you will not be coming to AES next week. If this is wrong, let me know. It has been several years since we last spoke in person.
-Jonathan
BTW, I was told you will not be coming to AES next week. If this is wrong, let me know. It has been several years since we last spoke in person.
-Jonathan
Being a die hard Mac guy this is something that is a very significant positive feature.
dave
Yes these are very important distinctions, and I believe should be emphasized. Linearity-wise sound cards are very good but the digital is mostly absent.
And no, unfortunately, can't make it to AES this year...
Are you going to show the Aver there? If so, wish you much success!
Jan
We are not exhibiting this year but I will attend. AverLAB is small enough that I just keep one in my briefcase wherever I go. After all, one never knows when they'll be wandering lost in the desert and stumble upon a hermit that won't provide you water until you can find the source of the distortion in his stereo. I try to be prepared. 
-Jonathan
-Jonathan
Interesting product indeed.
Just a few questions:
Do you have an European distributor ???
(Shipping stuff from the US to Sweden is "hell to pay", literally. Import fees, taxes and 25% VAT on everything, even the taxes. NO, I'm NOT kidding.)
3:d party software available or is it your SW only ???
I2S, SPI and I2C interfaces "available soon" ???
Is this a separatley purchased HW or just a firmware upgrade ???
Just a few questions:
Do you have an European distributor ???
(Shipping stuff from the US to Sweden is "hell to pay", literally. Import fees, taxes and 25% VAT on everything, even the taxes. NO, I'm NOT kidding.)
3:d party software available or is it your SW only ???
I2S, SPI and I2C interfaces "available soon" ???
Is this a separatley purchased HW or just a firmware upgrade ???
Jasse, here are the answers to your questions:
1) We don't have European distribution set up yet but are actively talking with people.
2) AverLAB is meant to use with our software only. We might eventually publish the command language to run it with 3rd party software. It is just a matter of justifying the documentation and support effort.
3) I2S, I2C and SPI interfaces are already in the box. We just haven't completed the UI development part of the software. We will have this enabled in one of the free software updates.
4) You can install the software on any computer. We just don't want you copying the hardware
-Jonathan
1) We don't have European distribution set up yet but are actively talking with people.
2) AverLAB is meant to use with our software only. We might eventually publish the command language to run it with 3rd party software. It is just a matter of justifying the documentation and support effort.
3) I2S, I2C and SPI interfaces are already in the box. We just haven't completed the UI development part of the software. We will have this enabled in one of the free software updates.
4) You can install the software on any computer. We just don't want you copying the hardware
-Jonathan
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