Gordon, We have tested the asynchronous PCM2912 with no results and the basic adaptive CMedia chips are (surprisingly) perfectly working with Windows (and TCXO). That is why we got lost I guess. Thanks for your help and explanations. I am sending you a private message for further information (not linked with CoreAudio).
JC > Le 22 août 2016 à 15:25, Gordon Rankin <[email protected]> a écrit : > > JC, > > If you are using a TCXO then your best option is to go ASYNC mode and yes > that will work with IOS and macOS as well as Windows and Linux. In ASYNC you > are the total master and the rate will be perfect. > > Knowing the TAS1020B, PCM2902 and some of the other older chips from products > I made decades ago. These products only use the XO input to create a PLL > Master Clock (and USB clock). The Adaptive rate is then based on the SOF from > the HOST and that timing is matched to the internal clock which then changes > the Master Clock and the sampling speed to match the host. So using a quality > TXCO to accomplish a really good 48K sample rate is not really going to > accomplish your goal. The true rate is going to be controlled from the host. > > You could use the TAS1020B or TUSB3200, which goes out of production at some > point. It is used in too many products to predict when. You would need the > Kiel 8051/52 development system and probably the eval board. Probably a > better idea would be a Microchip PIC32MX270 processor. The dev is cheap and > they have sample code for some of the operation. > > Thanks, > Gordon > > On 8/21/16 3:57 PM, Jean-Charles Rousset wrote: >> Thanks for your reply Gordon. >> >> What we have been trying to do is to RECORD sounds in iOS/macOS with our USB >> device as the master clock (TCXO) and iOS/macOS devices as the slave in >> order to get perfect samples. >> If I have understood correctly : >> - It cannot be achieved with ASYNC IN, as the sink (iOS) will be master. >> - Of course, it cannot be achieved by SYNC mode. >> - In ADAPTIVE mode, iOS should adapt its rate to what the USB device send. >> >> Maybe I understood it wrongly, but then, I have no idea how to send audio to >> iOS with iOS being clock slave. >> >> As I’m not recording audio for music but for timing measurement tool, I >> don’t need an ultra-high-quality audio. 16 bits / 48KHz is totally ok. But >> these 48KHz must be absolutely perfect (48.0000KHz..) >> >> Thanks ! >> >> JC >> >>> Le 21 août 2016 à 21:26, Gordon Rankin <[email protected]> a écrit >>> : >>> >>> JC, >>> >>> Adaptive of course will add jitter to either the input or output device >>> because of it's flow control being that of changing the Master Clock. Which >>> in turn changes the speed of the clocked device (I2S, L/RJ whatever). Parts >>> like the PCM2902 and really early TI parts were done (even early TAS1020 >>> code) before anyone really could take a look the consequences of the >>> protocols used. >>> >>> The XMOS software only works in ASYNC mode. You can use input, output both >>> etc... >>> >>> Maybe a better approach maybe to tell us what you are trying to accomplish >>> and maybe we could help you look for a better solution. Price or not, ASYNC >>> or SYNC is a much better ADC way than Adaptive. >>> >>> Brian is correct on the Windows front, unless you are only trying to >>> accomplish Full Speed UAC1 type products. >>> >>> Thanks, >>> >>> Gordon >>> > > -- > J. Gordon Rankin > Owner and Chief Scientist > ====== Wavelength Audio, ltd ======
_______________________________________________ Do not post admin requests to the list. They will be ignored. Coreaudio-api mailing list ([email protected]) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/coreaudio-api/archive%40mail-archive.com This email sent to [email protected]
