New analog signal generator

Our new (previously owned) analog signal generator arrived tonight (a Promax GV-698/11):

[lightbox title=”New analog signal generator” href=”../../blog/wp-content/uploads/2010/01/CIMG0205.jpg”][/lightbox]

Now, you might say “analog is dead” or “who cares about analog now that television has gone digital?” And the answer would seem to be “lots of people”. The reality is that as much as we like to talk about the advances in ATSC, ClearQAM, and the DVB variants, a large number of people out there still have analog and expect it to work. In the United States, the problem is especially evident since there are very few ways to access cable television without a settop box, meaning those people who do not wish to have an HD-PVR probably have a cable box connected to a tuner via an analog output.

Having a generator will make it easier to do testing of international standards (something that we do quite a bit of nowadays), and this generator in particular supports a variety of audio standards as well as teletext, meaning we can be confident that those functions will work even when we do not have access to a local signal source.

And finally, I personally have been quite dissatisfied with the general quality of a number of the different tuners and video decoders that I have worked with under Linux. Having a well calibrated signal source with a variety of patterns will allow me to improve the general picture quality for those devices. Whether that means making sure the registers for hue/saturation/contrast are properly programming, or being able to spot problems with formatting, resolution, or geometry.

It’s really easy to look at a TV picture and say “that doesn’t look right”. But figuring out what is actually wrong about the picture and what needs to be tweaked to fix it requires the right tools.

12 thoughts on “New analog signal generator

    • Nestor,

      No, you should not assume that there is any correlation between the decision to purchase an analog generator and a decision to commit to the thousands of dollars in man-hours that would be required to get analog working on the 2250.


      • does the dvico fusionhdtv7 dual express has any better luck? considering the cx23885 is used in a card that alread has analog support (hvr1800??) and someone even posted on the linuxtv mailing list stating a bit of promising results.

        • The cx23885 analog support *barely* works. There are a bunch of bugs in the v4l2 control implementation in the driver which Michael had started to work on. The driver needs a bunch of attention though before anyone can really claim that the “analog works” with common applications.


    • Jonathan,

      I’ve started to look at the cx23885 issues (hvr-1800/1850). I suspect Michael’s patches will need some additional work and cleanup before they can go upstream. If you’re talking about the 2250 though, that won’t be forthcoming anytime soon, given the amount of work required.


      • how about donations? I’m willing to donate at least 10$ I’m sure there are more than enough users who would see this supported so this should easily add up!

        please help us

  1. Nice!

    Regardless of how much digital is being put out there, I’d be surprised if that “last mile” of service strays from getting rid of analog service anytime soon.

    Looking forward to hearing a story about your experience with it.

  2. so let’s all stress Hauppauge to add analog support of USB-devices in Linux, so that someone is finally paying kernellabs to bring analog support to the v4l-usb framework.
    I want to drop my actual mythtv-box and use a cheaper nettop, but they aren’t coming with pci, so one can only use an usb-tuner. On top of this, here in Belgium we have one of the most dense cable network in the world, so we’re stuck to or analog or operator provided setop-boxes for dvb-c. Those cablenetwork operator are blocking any evolution for dvb-t extension. As I’m barely a script-kiddy, so I’m not able to be of any help. So, please, sent a mail to every manufacturer to have them add analog support in linux.

    • Hello Dan,

      Certainly, making it known to manufacturers like Hauppauge that you are using their products with Linux can only help encourage them to better support Linux. I wouldn’t restrict your comments to analog support though – in reality they apply to making the products work under Linux regardless of whether it’s analog or digital, or what transmission medium is used – broadcast, cable, or satellite.

      One of the big challenges I suspect the manufacturers have is that they have pretty much no idea what percentage of users use the product under Linux versus Windows, so any efforts made to improve the visibility of non-Windows users can only help.


  3. Ah yes v4l-usb framework analog support, I’m looking for this for a long time. I even wrote to the manufacturers, but they ignored me completely (no response at all). I was looking for a solution how to show to them how much people are interested in analog support for these tv cards.
    Is in contact (good realtions) with manufacturers like Hauppague, Yuan, etc? The idea is to prepare additional service on where people could request for a support or even register their product if that would be nessesary by the manufacturers. The possibility to be listened would be much higher than a single user request sent to the manufacturer directly. It would also show the precentage of users that uses their products under linux.
    What do you think?

    • Hello Yato,

      We have had conversations with Yuan about dvb-usb analog support, and I am in regular contact with people from Hauppauge and PCTV Systems. Given the razor-thin margins on these products, the *thousands* of units that would have to be sold to recover the cost have discouraged those companies from funding the work.

      And yes, we are talking about *thousands* of units. The reality is that Linux support is a ridiculously small market, and the vendors just cannot justify the cost.

      Others have suggested setting up some sort of way for users to voice their support on the kernellabs website. However, given how few people would actually respond (based on our experience with past surveys of this nature and user contributions to funding of open source drivers), showing the vendors the numbers will only reinforce their belief that there is virtually no market.


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