Part Number: TAS5805M
I’m seeing a significant 48KHz component at the output.
My input is 96K sps. Plotting points, the signal is a monotonic rise/fall.
I’m not using the internal DSP. LC filter, not ferrite bead.
It is acting as if my 96K input is being decimated and processed at 48K. Is this the case?
How might I reduce the 48KHz component? Alternate component?
Please share me your all I2C configurations and schematic to TAS5805. By the way, can you also capture your I2S (BCLK/LRCLK) waveform here for double check too?
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In reply to Alix Wan:
Schematic / PCB:
Ports 1/2 - replaced ferrite beads with the same LC filter as ports 3/4
All ports show the same issue. Muting left or right - no change.
I2C config: (same for ports 1/2 and 3/4)
/* reset DSP, volume ramping */
REG_CTRL2, DIS_DSP | CTRL2_MUTE
/* 384k switching freq, btl, bd mode */
REG_CTRL1, FSW_SEL_384K | DAMP_BTL | DAMP_MOD_bd
/* 64 bit/frame, 96k sample rate */
REG_SIG_CH_CTRL, BCK_RATIO_CONFIGURE_64FS | FS_MODE_96K
/* LTJ, 32 bit */
REG_SAP_CTRL1, DATA_FORMAT_LTJ | WORD_LENGTH_32
Excel plot of input points:
In reply to Sam Marshall:
It seems that you are using EVM board and find this issue. Then it would be easier for me to reproduce this issue in my lab.
Alix,1. Yes, I am using the EVM. However, I’ve hacked it a bit to run with a PSOC 6 EVM. So, I don’t have a PPC3 file. If I made one, I could not verify it.
For device B (LC filter)
Register 0x02, data 0x10 // Fsw 384kHz, BTL, bd
Register 0x03, data 0x03 // play
Register 0x28, data 0x5b // 64FS, 96K sample rate
Register 0x33, data 0x03 // I2S format, 32 bit word
(I’m using LTJ, since seems to be an 1 bit alignment bug between PSOC 6 and the 5805 in I2S mode. The 48kHz artifact is there in both modes)
I don’t know if there are any other registers that need to be set with the xmos sourcing the I2S.
2. PVDD - 24V Reducing the voltage clips the signal, but the region that is still linear has the same huge 48kHz artifact.
3. It happens regardless of waveform. A 10kHz sine is representative.
4. I’ve also tried it with the DC blocking disabled. Same trouble.
I was incorrect. Waveform seems to make all of the difference.
huge 48kHz artifact
WAV, IN TO 5805
The wave infinitely repeats. Values as follows:
For 5805EVM device B (LC filter)
PVDD = 24V
A 10kHz sine (and other freqs) looks exactly like what I’d expect. And, has only the expected artifacts.
48 vs 96kHz sample rate
5805 DSP is eating the signal. Why?
I can understand your configuration to TAS5805M and it turns out that 10K is checked to be ok.
Now, can you share a .wav or .mp3 file for my reproduce of the issue. I cannot understand you waveform description below:
The wave infinitely repeats. Values as follows:
Here's a 2 channel 96kHz WAV that should be playable from a PC. The above values repeat for several seconds. You should see something like the previous scope capture.
Thanks,SamClick here to play this audio clip
From your audio source, it turns out to be 10K "square wave" as below. With ~9.6KHz and its harmanoics.
As it is 96K Fs, TAS5805M is needed to choose 96K process flow and it can output waveform as below:
Please check your configurations and measure again. Tips below are for your reference:
Unfortunately, I’ve only got digital audio on my PC, so I was not able to verify levels. Here’s a new file, with the level shifted by 8 bits. Alternatively, can you adjust the volume on your end, until there is no clipping?
Sorry for the trouble.
Click here to play this audio clip
Can you install Audacity (free) to check your audio source file? On my side, even with your updated audio source file, it is a clipped square wave.
As a matter of fact, my volume is quite low (-24dB) and it won't cause clipping. Thanks！
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