Hi All,
What instrument do I need to generate digital signals in I2S or PCM format to test DACs with various waveforms, bit patterns, resolutions and sampling rates?
The instrument must output bitclok, frameclock, data ed eventually master clock.
I cannot afford the price of embedded systems like audio precision with DSIO options or similar...
Thanks!
What instrument do I need to generate digital signals in I2S or PCM format to test DACs with various waveforms, bit patterns, resolutions and sampling rates?
The instrument must output bitclok, frameclock, data ed eventually master clock.
I cannot afford the price of embedded systems like audio precision with DSIO options or similar...
Thanks!
May look at the USBStreamer from miniDSP who deal with 8 channels I/O I2S and SPDIF optical I/O ($105 boxed). Then drive them using a PC based Analyzer & Wave Generator.
Look search for JensH contribution, who build an isolation add-on board
Hp
You can try Scanalogic to generate and analyse signal. Other cheap possiblity is to use any -duino and create simple sketch for I2C (you can find examples on the net).
Actually I am intrigued by the Altor generator. I am one of that geeky guys that likes to have instruments watching me while working lol.
BTW it is a bit pricey for such a kind of stuff that comes with no certifications and no calibrations...despite well performing, I think...
BTW it is a bit pricey for such a kind of stuff that comes with no certifications and no calibrations...despite well performing, I think...
You may download a CD test from here vicol audio : support burn a blank CDR and grab I2S from a CD player to feed your DAC's.
Other solution is to use a software generator who generate the output to WAV files, which can be later written to a blank CD. This will limit you to 16/44K, but you may burn a DVD-A and do same thing for 24/192K. Of course in later case you need to use a DVD player.
Regards,
Tibi
Other solution is to use a software generator who generate the output to WAV files, which can be later written to a blank CD. This will limit you to 16/44K, but you may burn a DVD-A and do same thing for 24/192K. Of course in later case you need to use a DVD player.
Regards,
Tibi
Both Samuel and I have been using the Altor generator. I posted some details on it here. The data patterns for PCM are fine. The DSD stuff is approximate which is true for all DSD sources. I have used it up to 384/32 in I2S and everything works great. it can generate many signals and patterns you cannot get elsewhere and 352 + 384 are not available from Audio Precision. It doesn't have jitter tolerance tests although you could provide the master clock with modulation for those tests. Its on my to do list the next time I need to test for jitter tolerence and jitter reduction.
I'm not sure what you would calibrate of a data generator? The only calibration on the $120K BERT I use for HDMI is the signal levels/transitions and that issue does not exist for a pure data generator.
Anyone developing a DAC should have an Altor generator.
I'm not sure what you would calibrate of a data generator? The only calibration on the $120K BERT I use for HDMI is the signal levels/transitions and that issue does not exist for a pure data generator.
Anyone developing a DAC should have an Altor generator.
Demian, thanks for advertisement 🙂
Really - what can be calibrated in this design?
Clock frequency? Yes, maybe.
SPDIF or I2S bus voltage levels? Not critical due to a big tolerance.
TOSLINK - nothing.
Analod outputs voltage? Yes, but this is not the main device's feature, and also the tolerance can be high.
P.S. About certifications - the main goal of most certifications, it to bring money to the certificators....
There ara certificated devices on the market, but they have many "zeroes", at the end of their price number. Because - who at the end pay for certifications? The customer.
Really - what can be calibrated in this design?
Clock frequency? Yes, maybe.
SPDIF or I2S bus voltage levels? Not critical due to a big tolerance.
TOSLINK - nothing.
Analod outputs voltage? Yes, but this is not the main device's feature, and also the tolerance can be high.
P.S. About certifications - the main goal of most certifications, it to bring money to the certificators....
There ara certificated devices on the market, but they have many "zeroes", at the end of their price number. Because - who at the end pay for certifications? The customer.
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Hi Alex!
Just placed the order. And I am looking forward to have the generator asap in my greedy and geeky hands.
Just placed the order. And I am looking forward to have the generator asap in my greedy and geeky hands.
Don't worry, I have some units ready 🙂
Let me provide the final test before shipment, and then I will send it to you.
Let me provide the final test before shipment, and then I will send it to you.
Or even higher sample rates
Soon I plan to add a combine x2, x4, x8 speed on capture & render using multi-channels like the 8 channels I2S USBStreamer. The channel shifts has to be done on an external HW logic.
JensH suggested to build such 786khz solution for the upcoming AKM ADC/DAC 😀
Hp
Soon I plan to add a combine x2, x4, x8 speed on capture & render using multi-channels like the 8 channels I2S USBStreamer. The channel shifts has to be done on an external HW logic.
JensH suggested to build such 786khz solution for the upcoming AKM ADC/DAC 😀
Hp
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