English Amiga Board


Go Back   English Amiga Board > Search Forums

Showing results 1 to 40 of 866
Search took 0.08 seconds.
Search: Posts Made By: Thomas Richter
Forum: Coders. Asm / Hardware Yesterday, 14:50
Replies: 141
Views: 7,178
Posted By Thomas Richter
Sorry to sound confused. I'm looking at the total...

Sorry to sound confused. I'm looking at the total distortion, i.e. "noise" (the word is not quite appropriate) that is caused by quantization, plus uncorrelated noise, i.e. from imperfections of the...
Forum: Coders. General Yesterday, 00:07
Replies: 19
Views: 750
Posted By Thomas Richter
Err, there is no error I am aware of. For timing,...

Err, there is no error I am aware of. For timing, use the timer.device. It times correctly.



There were link-libraries in 1.3 times to support them. It's not a feature of the A1200 to include...
Forum: Coders. General 23 January 2021, 23:58
Replies: 19
Views: 750
Posted By Thomas Richter
Not any more or less than on Kick 1.3. Actually,...

Not any more or less than on Kick 1.3. Actually, there is Exec RemTask(), but even though this removes the task from getting scheduled by the system, it does not stop pending I/O operations the task...
Forum: Coders. Asm / Hardware 23 January 2021, 22:48
Replies: 141
Views: 7,178
Posted By Thomas Richter
For fun, I'm attaching here the residual spectra...

For fun, I'm attaching here the residual spectra for the PC and the Amiga. Note that both are amplified by 6 bits (i.e. approximately 36dB). On the PC side, you see that there are some low-power...
Forum: Coders. Asm / Hardware 23 January 2021, 22:19
Replies: 141
Views: 7,178
Posted By Thomas Richter
Thanks, I tought about this, but I believe there...

Thanks, I tought about this, but I believe there is something wrong here with the last step, and applying Matlab's snr() naively. The preprocessing steps are of course all fine, I'm doing the same.
...
Forum: Coders. Asm / Hardware 23 January 2021, 22:06
Replies: 5
Views: 356
Posted By Thomas Richter
No, there is much more about it. Memory...

No, there is much more about it. Memory relocation is one thing it can perform, but it also provides (optional) write-access to pages, defines the caching mode of pages such that chip or I/O...
Forum: Coders. Asm / Hardware 22 January 2021, 09:28
Replies: 8
Views: 413
Posted By Thomas Richter
Yes. Use the operating sytem. input.device or the...

Yes. Use the operating sytem. input.device or the IDCMP of the window of your program.
Forum: Coders. Scripting 22 January 2021, 08:49
Replies: 1
Views: 196
Posted By Thomas Richter
That alone doesn't work, at least not with the...

That alone doesn't work, at least not with the regular CON: handler of the operating system. You also need to switch CON: to the raw mode, which I would not know how to do from ARexx. The CON:...
Forum: Coders. C/C++ 19 January 2021, 21:38
Replies: 5
Views: 320
Posted By Thomas Richter
GetMsg() is not exactly the right way to handle...

GetMsg() is not exactly the right way to handle IO request. You send out the request with SendIO(). You test whether the request is done with CheckIO(), which returns the request when done, or NULL...
Forum: Coders. Asm / Hardware 17 January 2021, 16:47
Replies: 141
Views: 7,178
Posted By Thomas Richter
That's called "subjective quality", which is...

That's called "subjective quality", which is certainly the gold standard. However, that wasn't quite the starting point. Maybe the Paula "14 bit audio" is satisfactory for some listeners - and I do...
Forum: Coders. Asm / Hardware 17 January 2021, 16:44
Replies: 141
Views: 7,178
Posted By Thomas Richter
Fine, but how do you feed that into your speakers...

Fine, but how do you feed that into your speakers from a computer? The PC soundcard cannot provide a PWM modulated signal with pulse modulation frequency at Mhz rate. They typically play back at...
Forum: Coders. Asm / Hardware 17 January 2021, 16:42
Replies: 141
Views: 7,178
Posted By Thomas Richter
Because they measure something different. See my...

Because they measure something different. See my answer below. If you just turn down the volume until the signal fades away completely, you ignore all other noise that may arise on the channel, such...
Forum: Coders. Asm / Hardware 17 January 2021, 16:40
Replies: 141
Views: 7,178
Posted By Thomas Richter
That measures the smallest/least significant...

That measures the smallest/least significant quantization level, but not the SNR. In other words, this type of measurement allows you to identify the smallest step the (implicit) quantizer can...
Forum: Coders. Asm / Hardware 17 January 2021, 14:57
Replies: 141
Views: 7,178
Posted By Thomas Richter
Absolutely, you should. Though it also requires a...

Absolutely, you should. Though it also requires a high quality analog part. The SB Live! here doesn't do that. It's not what is available as raw data on the CD as well, though every decent CD player...
Forum: Coders. Asm / Hardware 17 January 2021, 14:53
Replies: 141
Views: 7,178
Posted By Thomas Richter
Unfortunately, that is exactly what we have:...

Unfortunately, that is exactly what we have: Digitally sampled analog audio waves. I tried to provide tools to generate such waves with any frequency and any sampling frequency you like.



...
Forum: Coders. Asm / Hardware 17 January 2021, 00:43
Replies: 141
Views: 7,178
Posted By Thomas Richter
It's also interesting to look (or hear) the error...

It's also interesting to look (or hear) the error signal, which is easily arranged with the algorithm provided. For the PC output, the error signal is so low I cannot hear anything, and audacity's...
Forum: Coders. Asm / Hardware 17 January 2021, 00:04
Replies: 141
Views: 7,178
Posted By Thomas Richter
With a 16 bit quantizer? How is that supposed to...

With a 16 bit quantizer? How is that supposed to happen? With ~6dB per Bit (you should know that), you are limited to 96dB. With 14 bit, you should be able to get around 84dB, only 12dB less...
Forum: Coders. Asm / Hardware 16 January 2021, 23:58
Replies: 141
Views: 7,178
Posted By Thomas Richter
You are invited to compute better, really. I...

You are invited to compute better, really. I provided the algorithm, and this is what I get with the equipment I have. Note that there is additional noise in the loop (quantized twice), plus some...
Forum: support.Other 16 January 2021, 17:21
Replies: 5
Views: 807
Posted By Thomas Richter
Low-memory reservation is done very early during...

Low-memory reservation is done very early during bootstrap. This requires ROM support to work reliably.
Forum: Amiga scene 16 January 2021, 17:13
Replies: 15
Views: 1,716
Posted By Thomas Richter
Are you sure you didn't mix these two up? I have...

Are you sure you didn't mix these two up? I have here a 1C12R mask that is qualified as MC-part, not as XC part. It would make more sense if 0C35H is the earlier mask.
Forum: Coders. Asm / Hardware 16 January 2021, 15:17
Replies: 141
Views: 7,178
Posted By Thomas Richter
Please don't me call stupid. Please look at the...

Please don't me call stupid. Please look at the test programs I provided. It does adjust to "the starting point" (actually, that is called "the phase"), and it does adjust to the frequency (actually,...
Forum: Coders. Asm / Hardware 16 January 2021, 15:14
Replies: 141
Views: 7,178
Posted By Thomas Richter
Instead of making claims, please measure. There...

Instead of making claims, please measure. There have been enough false claims already here. As in "The Amiga never creates dropouts, never!". Also simply wrong on my setup.
Forum: Coders. Asm / Hardware 16 January 2021, 15:13
Replies: 141
Views: 7,178
Posted By Thomas Richter
That depends on how you measured, and with which...

That depends on how you measured, and with which equipment. The results are relative to the measurement chain. 16bit output should give you approximately 96dB, probably 90dB with good equipment, but...
Forum: Coders. Asm / Hardware 16 January 2021, 15:11
Replies: 141
Views: 7,178
Posted By Thomas Richter
Repeated the experiment with EaglePlayer. The...

Repeated the experiment with EaglePlayer. The result is pretty much the same, it is 31.80 dB, whereas the previous play16 output was 31.87dB, which is identical within the expected tolerance. Video...
Forum: Coders. Asm / Hardware 16 January 2021, 11:49
Replies: 141
Views: 7,178
Posted By Thomas Richter
Unfortunately, that is not the situation we have....

Unfortunately, that is not the situation we have. We have an 8 bit DAC multiplied by a 6-bit DAC, added to another 8-bit DAC. This is how the output is produced, not by a 14-bit DAC. This type of...
Forum: Amiga scene 15 January 2021, 16:11
Replies: 122
Views: 6,405
Posted By Thomas Richter
Well, I'm not sure whether I'm excited or not......

Well, I'm not sure whether I'm excited or not... I believe the real advantage is that you get a machine that is (hopefully) solid and stable, and in a good technical condition, with warantee on it....
Forum: Amiga scene 15 January 2021, 13:09
Replies: 15
Views: 1,716
Posted By Thomas Richter
The reason why these powers of ten are in the...

The reason why these powers of ten are in the constant ROM is that they are needed for the conversion of packed decimal to IEEE extended precision and back.
Forum: Amiga scene 14 January 2021, 21:28
Replies: 122
Views: 6,405
Posted By Thomas Richter
Of course, much more serious problems, which is...

Of course, much more serious problems, which is exactly the reason why MS ditched it. AmigaOs was never ditched by CBM, CBM died before that happened, though it was only a matter of time when that...
Forum: Amiga scene 14 January 2021, 15:49
Replies: 122
Views: 6,405
Posted By Thomas Richter
Not really. If it would, we wouldn't have...

Not really. If it would, we wouldn't have Forbid()/Permit() SysBase->TDNestCount which prevents multi-core execution, and we wouldn't have struct BitMap which is a major annoyance for non-planar...
Forum: Coders. General 13 January 2021, 19:54
Replies: 3
Views: 433
Posted By Thomas Richter
Note that the ZZ9000 driver is maintained by...

Note that the ZZ9000 driver is maintained by Lucas, not by me, so in case of trouble, please contact him. Sprite sizing requires proper annotation through some of the flags provided for the library....
Forum: support.WinUAE 13 January 2021, 19:52
Replies: 14
Views: 789
Posted By Thomas Richter
The 68040 does the full operand fetch and...

The 68040 does the full operand fetch and provides a very large stack frame on which the fpsp can find all missing operands. The 68060 doesn't do that, so the FPSP has to decode the opcode itself and...
Forum: Amiga scene 13 January 2021, 17:58
Replies: 198
Views: 5,927
Posted By Thomas Richter
Posted April 1st. (-:

Posted April 1st. (-:
Forum: Amiga scene 13 January 2021, 17:57
Replies: 198
Views: 5,927
Posted By Thomas Richter
It would probably qualify as 68EC080, without a...

It would probably qualify as 68EC080, without a full precision FPU, and without a full MMU.
Forum: Coders. Asm / Hardware 13 January 2021, 15:24
Replies: 9
Views: 517
Posted By Thomas Richter
That depends on the statistics of the branches....

That depends on the statistics of the branches. An alternative approach would be to store the branch destination in an address register that either points to the real target, or to a single RTS. This...
Forum: Coders. Asm / Hardware 13 January 2021, 06:31
Replies: 141
Views: 7,178
Posted By Thomas Richter
I'm not even sure what you want to say here.

I'm not even sure what you want to say here.
Forum: Coders. Asm / Hardware 13 January 2021, 06:30
Replies: 141
Views: 7,178
Posted By Thomas Richter
Then chose it differently. The tools I posted...

Then chose it differently. The tools I posted allow you to specify the frequencies. Though the phase drift aka incorrect frequency is not the real problem here. It's compensated.
Forum: Coders. Asm / Hardware 12 January 2021, 23:22
Replies: 141
Views: 7,178
Posted By Thomas Richter
For the test frequency used here (441Hz), we are...

For the test frequency used here (441Hz), we are well away from the critical frequency of the filter of any of the machines. Since an ideal R/C filter is linear, the output of a sine wave (such as...
Forum: OT - Technical 12 January 2021, 18:25
Replies: 29
Views: 2,630
Posted By Thomas Richter
Impressive. The 6502 is a very unfriendly target...

Impressive. The 6502 is a very unfriendly target for a C compiler.
Forum: Coders. General 12 January 2021, 18:21
Replies: 3
Views: 433
Posted By Thomas Richter
OpenScreenTags() is fine, you don't need much...

OpenScreenTags() is fine, you don't need much else. I'm attaching the P96 internal test program for you, this should do it.
Forum: Coders. Asm / Hardware 12 January 2021, 18:16
Replies: 141
Views: 7,178
Posted By Thomas Richter
The test input is just a sine wave. The only...

The test input is just a sine wave. The only effect a preemphasis (in frequency space) has is a change of the signal amplitude. However, the signal amplitude is part of the fitting parameters of the...
Showing results 1 to 40 of 866

 
Forum Jump

All times are GMT +2. The time now is 10:06.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Page generated in 0.12835 seconds with 10 queries