Spectrum analysys of perceptual codecs is useless
on
AAC vs. OGG vs. MP3
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· Score: 1
"Spectrum analysis was used to see which format did the best job of maintaining the shape of the original waveform."
One of the things a perceptual encoder does is to transform the spectral content in sunch a way that it is cheaper to represent the remainder while not affecting how the result sound to the human ear.
Using spectral analysis to compare the encoders might not show anything other than which encoder is worse in optimizing the spectrum.
The only proper way to test the codecs is to do a rigorous double blind study with the original material as refrence.
I brought my iPod skiing (downhill, alpine). Two days with outside temperatures varying between -10C to 0C (Between the top and the bottom of the mountain) 6 hours each day.
While the unit itself wasn't subjected to outside temperature, it did get exposed to a fair bit of humidity inside the jacket as well as the occational bump and bruise from falls.
The only problem is that the remote control connection is too loose som somtimes it worked loose. Music wasn't interrupted but the remote failed to work until the connector was reseated.
(Also the remote wire is poorly buildt. The insulator jacket works loose from the jack leaving the the wires with no strech protection. This I fixed with a hot-glue gun)
I suggest you look around more then, and maybe even RTFA. This company has the response of their 24-bit A/D convertor right there on the page linked to in this story. Duh.
I have seen the plot and it doesn't look like a 24 bit converter to me. More like 18.5 bits.
You can pretty easily get a mic which will give you 144db of dynamic range, they're just not cheap. Here's a mic that will handle 160 db maximum.
It may not have 160db SNR but I would willing to bet that it has an SNR much better that the ninety something 16bit audio allows for.
The url just gives me: Invalid Item Number, or Product Not Found.
You claim it wil 'handle' 160dB. What do you mean by this? It looks to me like you are quoting max spl rating, which does not at all reflect on it's dynamic range or SNR figures.
As for your bet on it's SNR capability; that is pure speculation.
Have a look at the graphs for our new Mic2496 on our Web site: http://www.core-sound.com/HighResRecorderNews.html
24-bit at up to 96 KS/s. Operates on one 9 Volt battery. Noise levels are down over 120 dB below 0 dBFS. Dynamic range of over 120 dB.
While the graph indicates a level of performance far surpassing what is needed for a regular recording, 24 bits it isn't.
Looking at the frequency spectrum, you have demonstrated a dymamic range of approx 110dB, or 18.5 bits.
If you can raise the input signal voltage by 33dB (that is approx 2.2V in your case) without affecting the noise floor then I will accept that you have 24 bit capability.
This was my point exactly regarding monster cable, which is basically low-gauge braider copper cabling.
Actually monster and other 'exotic' audio cable manufacturers sell mostly 16 and 14 gauge wires as speaker cable. The extremely thich cables some of these sell are pretty much only insulation.
Any cabling you buy in audio stores will cost at least 3x as much as equivalent cabling bought at electrical supply shops.
I work at a microelectronics shop, and with 20 EEs around the lunch table, woe to the one who mentions 'high-end' audio cables and means it.
(We work motly with RF, so yes we are pretty well versed in transmission line effects ant the like)
Expensive audio cables is a hoax. There, that is really all you need to know.
To elaborate: most audio cable companies tries to pull somthing about transmission line effects or impedance matching (same thing) as the virtue of just their cables. This is utter bullshit as transmission line effects no not come into play before the cable is a significant fraction of the shortest wavelenght. (cable propagation is somwhere around 0.3-0.9c, highest intresting frequency is 20KHz. Finding the cable lenghts where transmission line effects matter is left as an excersice for the reader Hint: use 1/16th wavelength as a pretty paranoid fraction of wavelenght before TL effects matter)
The only thing that matters in your choice of speaker cable is that you want to keep series resistance much much less than the speaker impedance. This usually mean 10-14 gauge cable for 2-4m runs. The copper quality in regular cables are not, contrary to the 'ethusiast' cable makers claims, any worse than in expensive cables. For those of you looking at silver cables: drop it, just buy thicker copper.
You are not going to get 24 bits recordings of anything battery operated.
The level of precision recuired to even begin to approach 24 bits recuire very high biascurrents in the device.
Actual 24 bit conversion is actually extremely hard. I am not aware of any standard device capable of this level of precision at audio frequencies, let alone 200KHz.
Also you will not find any mic or concert venue enabling you to deliver 144dB dynamic range into the adc. You will likely actually get somwhere between 30-60dB
Note: Do not confuse the wordlength with the precision. There are many AD and DA devices who output a lot more bits than they actually can deliver data for. This is done to justify the audio-biz need for specmanship. (stick a '24' bit dac in there so we can write it on the front panel, never mind the device is propably only capable on 16-18 bits)
note that SACD is a different format, called DSD, and is not technically 24/196 in the fashion the original poster intended (PCM).
DSD is supposed to be the raw output of a 2.8MHz delta-sigma modulator (similar, but slightly inferior the front end of virtually any audio AD).
You can consider this a 2.8MHz PCM signal with one bit words. This give you a lousy signal to noise ratio, however the modulation casues most of the noise to be in the HF part of the spectrum, leaving the audio part clean.
Normally you want to filter out the noise and drop the sampling rate (this is called decimation and is the back-end in the earlier mentioned ADs), leaving only information.
I can only guess that the reason sony went with a system that spends so many bits on storing just ultrasonic noise is that this is so nuts, noone has patented it before.
You can, however, get upsampling DACs that do indeed show an impressive improvement (even though they shouldn't) when converting 16/44.1 PCM to 24/196 PCM
upsampling can't add anything that isn't there. the only reason you want to change the format for conversion is to adapt the signal to your analog DA backend. This normally mean a digital delta-sigma modulation to a 1-5 bit word with sample rate somwhere between 0.5-4 MHz. Going through 24/196 is totally and utterly pointless as this format will absolutely not match any concievable analog backend
" Let me set the record straight: OC'd processors NEVER run stable. If they did, Intel would have clocked them in the higher bin or whatever."
Nope. It is very unlikely that the distribution of max reliable performance after bin-sort is exactly the same performance distribution the market wants.
If there is a larger market for 1.8GHz CPUs that output from bin-sort into the 1.8GHz max bin then you mark down some 2.0GHz parts.
Also note that the bin-sort is done at max rated temperature if the OCer keeps his die at a lower temp then it will likely run stable at higher speeds.
you seem to primarily focus on shortcomings in the GUIs of the tools. You should realise that the GUI is not the primary UI of these tools. Practcally all EDA tools are script based (usually tcl) and anyone who use them for real will hardly ever use the GUI.
Performance and quality of results are much more important than GUI niceties.
As for the price, I think you left out a zero. While there are a few tools that costs as little as $10000, prices of $100000-$400000 are not uncommon.
The bitstream in SACD is the output of a pretty simplistic delta sigma modulator. (Moden audio ADCs use multibit delta sigma modulators).
The fuction of a DS modulator is to shape the quantification nose such that it occurs outside the useful band. (in this case up to 20KHz). The 120dB dynamic range figure for SACD is only valid for DC. At the upper end of the audio spectrum it is no better or less than that of an ordinary CD.
Storing the raw output of the DS modulator strikes me as extremely silly as you will use most of your bits to store unwanted HF noise.
The only sensible thing is to filter the output and just store the information, but... oops... we have done that since last world war and patenting this now would be difficult. Enter SACD: so silly we can patent it.
The most significant advantage with using bluetooth is the marketing value of bluetooth and the fact that 2.4GHz devices may be sold all over the world. Other ISM bands differ i different regions.
There is also a potential benefit for the consumer that they might use a common reciever to hook up several bluetooth devices, I doubt if this advantage will be particularly significat in this product's lifetime though.
The price is naturally set to what logitech thinks the market is willing to pay, however with regard to your comment: Remember that a baseband controller does not a bluetooth device make. You also need the housing, RF tranciever and antenna. Which will propably drive total parts cost up towards $10-15. Considering that devices costing at retail around $30 will typically have to keep parts cost below $3 (if it is a high volume device), you'd expect a higher price on this device.
That's what I thought till I went to Best Buy: 6 foot digital coax - $13 [bestbuy.com]. I actually remember paying $8 or $9 at the store but that was a while ago. Sure beats Circuit City, where the mofo tried to sell me a $40 digital cable. Ha!
You've been had. Digital coax cable is just regular 75 ohm cable with RCA jacks (though the tolerances are so wide you could also use a rusy coathanger).
This happens to be the same spec as for composite video. Chanses are that you have a pile of these lying around as they tend to come bundled with just about any piece of AV equipment. If not you should be able to pick them up for $2-6.
Opticals are less commonly bundled, but should be possible to find for around $6-8.
I have yet to see a universal remote that actualy:
A: Was universal
Not seen any ir based remote my pronto can't handle yet.
B: Did not take a universally large amount of time to setup.
That depends on what you mean by large. A pronto is configured on a computer so that speds things up a great deal.
And quite frankly I should not need a 30 button remote for just my DVD player. This is why I only view DVDs on my computer, faaar easier, don't have to switch around audio and video inputs until hell freezes over, then select the proper audio decompression scheme, then select the proper surround sound scheme, and THEN sit down and 'enjoy' the movie, and then have the honor of switching all that shit BACK to watch regular TV.
Or do is I do: have a big button that says DVD on the remote, which when pressed selects correct input on the TV and amp, then reconfigures the remote display for DVD playback control. My amp is five years old, but even that is able to correctly autoselect decoding, what kind of archaic hardware have you been using?
No thank you. . . . I can pop a DVD in my computer's drive and it starts playing, and when it is done I take it out, close the program, and I am done. End.
Funny.. After several hours of configuring DVD playback software on a PC I found that the playback software wasn't able not to reformat anamorphic material. Since the videoencoder was unable to sync to 16:9 square pixel modes (internal videoencoders in gfx cards does not have component outputs, which I require). End result was that the PC based system was unable to output 16:9 anamorphic pictures, resulting in significant image degradation.
And don't even get e started on the general unreliability and unfriendlyness on PC surround sound systems. Most of the time, it seems they assume you want some strange effects applied, or they refuse to decode at all. In contrast in my regular DVD setup i just have a regulat 75 ohm cable from the digital out of the DVD to the DVD s/pdif input of the amp, the rest just works.
A high enough bitrate will be impossible to tell apart from an analogue source, sure. But bitrates still make things sound a lot better. The best way to prove this is to get you go to a place that sells sound systems that can handle Super Audio CDs [superaudio-cd.com]. When I did this they played me two recordings of a guitar concert, one regular CD (44.1kHz, 16-bit), the other a SACD (~2.8MHz, 1-bit). None of the other settings were changed. The difference is startling.
That's because the two are mixed differently so you should hear a difference. (Yup. different mixes same disc.)
The oly real reason that SACD exist is that sony wanted to grab a slice of the audio on DVD market. An to really make som cash you need to control the standards. Unfortunately for sony the reasonable way to do things were allready well known (store PCM), and they needed somthing novel to patent.
Thus were born DSD encoding (as is used on on SACD). The fact of the matter is that DSD encodes far less information than a similar bitrate PCM stream (SACD is comparable with CDDA in fidelity) as most of the signal energy is spent in storing noise. (Take a look at the output of a delta sigma noise shaping modulator and you will see what I mean).
You can of cource not actually hear this as CDDA allready goes well beyond what is humanly perceptible. Though as SACD mandates a single bit encoding it may be possible to create pathological signals which will sound markedly worse in SACD that what might be possible on CDDA. (Single bit SD conversion has some problems with dithering)
> With the primary feature that you can play and control your xbox from literally anywhere in the world. No, with the primary feature that they can play and control your xbox from literally anywhere in the world...
Given MS security track record, it actually means anyone can play and control your xbox (with the possible exception of you).
Unfortunately the xst synthesis software that xilinx provides is next to useless. If you do your own optimizations, then fine. If you rely on the synthesis software to optimize (and quite frankly handcrafting logic optimizations isn't my idea of fun) then you won't get very good results.
Xst isn't terribly compatible with regular synthesizable VHDL either. Expect some revriting.
As for fitting a cpu core on a fpga: Sure cpu cores aren't particularly big (even on state of the art designs, the die area is largely used for cache rather than core.)
As for pipeling: Sure you can get it up to a 100 MHz or so, but pipelining incurs penalties. You can very easily be bitten by data dependencies.
As for size, we are working on a virtex II 6000, and it can barely fit a dprototype of a design which will occupy approx 4mm^2 of silicon area on the final 0.18um asic (granted the design would have been done somwhat differently if we actually targeted the fpga)
Such cards do exist. They generally cost at least a few thousand dollars though.
Also don't expect a fpga based card do outperform a dedicated circuit. Youll need an order of magnitude (at least) more silicon area to make a circuit on an fpga than on an asic, and you can never hope to match the speed.
Furthermore you will need appropiate software to synthesize and run place and route on the fpga. These generally cost from around $10000 each, Though prices are negotiable. If you can manage with less you might be able to make do with the vendor provided synthesis software, but don't expect good results. Synplicity or leonardo spectrum (to be replaced with Precision Synthesis) are the good choices.
A modchip is usually a PIC [robotbooks.com] or ASIC [techtarget.com] programmed/designed to be used as a hardware "patch" for mass-produced hardware.
I seriously doubt anyone have made the investment of doing a asic of a modchip.
Considering that even a very simple design will cost you several $100K, I doubt if the mod-chip-makers have that kind of funds or are able to recover such costs (not to mention the difficulty of getting a design house to accept such a low-income, high-risk job)
More likely candidates are flashable microcontrollers (not just PICs, though those are very popular) or FPGAa.
Huh? Doesn't.13u imply more chips per wafer, and therefore a lower cost basis?
As long as your chip is mostly digital, then yes it might.
However you must evaluate if the longer design time, increased mask costs and potentially higher tool costs (timing closure is a bitch on.18 and better) can be offset by the higher yield/wafer. (i.e. if you excpect enough volume to make it worthwile)
As for circuits with analog components. These don't nearly shrink as much as digital (indeed they often grow due to the exotic solutions swhich might be needed) with smaller processes.
The primary obstacle for continuing develompment on our current path will likely not be technological but rather financial.
New fabs are increasing in cost at a dramatic rate, unless the semiconductor market increases it's growthrate substantially we'll likely see that while technologically possible some next stage development of CMOS will be economically infeasible as a fab won't be able to recover the cost of building it over it's lifetime.
We are not there yet, and not likely to get there for another ten years, but if present developments continue we will get there some 10-20 years from now.
Slashdot Mirror
"Spectrum analysis was used to see which format did the best job of maintaining the shape of the original waveform."
One of the things a perceptual encoder does is to transform the spectral content in sunch a way that it is cheaper to represent the remainder while not affecting how the result sound to the human ear.
Using spectral analysis to compare the encoders might not show anything other than which encoder is worse in optimizing the spectrum.
The only proper way to test the codecs is to do a rigorous double blind study with the original material as refrence.
I brought my iPod skiing (downhill, alpine). Two days with outside temperatures varying between -10C to 0C (Between the top and the bottom of the mountain) 6 hours each day.
While the unit itself wasn't subjected to outside temperature, it did get exposed to a fair bit of humidity inside the jacket as well as the occational bump and bruise from falls.
The only problem is that the remote control connection is too loose som somtimes it worked loose. Music wasn't interrupted but the remote failed to work until the connector was reseated.
(Also the remote wire is poorly buildt. The insulator jacket works loose from the jack leaving the the wires with no strech protection. This I fixed with a hot-glue gun)
I use it whie walking all the time.
I suggest you look around more then, and maybe even RTFA. This company has the response of their 24-bit A/D convertor right there on the page linked to in this story. Duh.
8 36 38141149239237800975/search/g=rec/detail/base_id/5 5354
I have seen the plot and it doesn't look like a 24 bit converter to me. More like 18.5 bits.
You can pretty easily get a mic which will give you 144db of dynamic range, they're just not cheap. Here's a mic that will handle 160 db maximum.
http://www.musiciansfriend.com/srs7/sid=0304141
It may not have 160db SNR but I would willing to bet that it has an SNR much better that the ninety something 16bit audio allows for.
The url just gives me: Invalid Item Number, or Product Not Found.
You claim it wil 'handle' 160dB. What do you mean by this? It looks to me like you are quoting max spl rating, which does not at all reflect on it's dynamic range or SNR figures.
As for your bet on it's SNR capability; that is pure speculation.
Have a look at the graphs for our new Mic2496 on our Web site: http://www.core-sound.com/HighResRecorderNews.html
24-bit at up to 96 KS/s. Operates on one 9 Volt battery. Noise levels are down over 120 dB below 0 dBFS. Dynamic range of over 120 dB.
While the graph indicates a level of performance far surpassing what is needed for a regular recording, 24 bits it isn't.
Looking at the frequency spectrum, you have demonstrated a dymamic range of approx 110dB, or 18.5 bits.
If you can raise the input signal voltage by 33dB (that is approx 2.2V in your case) without affecting the noise floor then I will accept that you have 24 bit capability.
We are the pentium of Borg! Mathmatics is irrelevant. Division is futile. You will be approximated.
:)
Ooohh... Star Trek refrence AND intel bashing... I sense geek cred is rising.
This was my point exactly regarding monster cable, which is basically low-gauge braider copper cabling.
Actually monster and other 'exotic' audio cable manufacturers sell mostly 16 and 14 gauge wires as speaker cable. The extremely thich cables some of these sell are pretty much only insulation.
Any cabling you buy in audio stores will cost at least 3x as much as equivalent cabling bought at electrical supply shops.
I work at a microelectronics shop, and with 20 EEs around the lunch table, woe to the one who mentions 'high-end' audio cables and means it.
(We work motly with RF, so yes we are pretty well versed in transmission line effects ant the like)
Expensive audio cables is a hoax. There, that is really all you need to know.
To elaborate: most audio cable companies tries to pull somthing about transmission line effects or impedance matching (same thing) as the virtue of just their cables. This is utter bullshit as transmission line effects no not come into play before the cable is a significant fraction of the shortest wavelenght. (cable propagation is somwhere around 0.3-0.9c, highest intresting frequency is 20KHz. Finding the cable lenghts where transmission line effects matter is left as an excersice for the reader Hint: use 1/16th wavelength as a pretty paranoid fraction of wavelenght before TL effects matter)
The only thing that matters in your choice of speaker cable is that you want to keep series resistance much much less than the speaker impedance. This usually mean 10-14 gauge cable for 2-4m runs. The copper quality in regular cables are not, contrary to the 'ethusiast' cable makers claims, any worse than in expensive cables. For those of you looking at silver cables: drop it, just buy thicker copper.
You are not going to get 24 bits recordings of anything battery operated.
The level of precision recuired to even begin to approach 24 bits recuire very high biascurrents in the device.
Actual 24 bit conversion is actually extremely hard. I am not aware of any standard device capable of this level of precision at audio frequencies, let alone 200KHz.
Also you will not find any mic or concert venue enabling you to deliver 144dB dynamic range into the adc. You will likely actually get somwhere between 30-60dB
Note: Do not confuse the wordlength with the precision. There are many AD and DA devices who output a lot more bits than they actually can deliver data for. This is done to justify the audio-biz need for specmanship. (stick a '24' bit dac in there so we can write it on the front panel, never mind the device is propably only capable on 16-18 bits)
note that SACD is a different format, called DSD, and is not technically 24/196 in the fashion the original poster intended (PCM).
DSD is supposed to be the raw output of a 2.8MHz delta-sigma modulator (similar, but slightly inferior the front end of virtually any audio AD).
You can consider this a 2.8MHz PCM signal with one bit words. This give you a lousy signal to noise ratio, however the modulation casues most of the noise to be in the HF part of the spectrum, leaving the audio part clean.
Normally you want to filter out the noise and drop the sampling rate (this is called decimation and is the back-end in the earlier mentioned ADs), leaving only information.
I can only guess that the reason sony went with a system that spends so many bits on storing just ultrasonic noise is that this is so nuts, noone has patented it before.
You can, however, get upsampling DACs that do indeed show an impressive improvement (even though they shouldn't) when converting 16/44.1 PCM to 24/196 PCM
upsampling can't add anything that isn't there. the only reason you want to change the format for conversion is to adapt the signal to your analog DA backend. This normally mean a digital delta-sigma modulation to a 1-5 bit word with sample rate somwhere between 0.5-4 MHz. Going through 24/196 is totally and utterly pointless as this format will absolutely not match any concievable analog backend
" Let me set the record straight: OC'd processors NEVER run stable. If they did, Intel would have clocked them in the higher bin or whatever."
Nope. It is very unlikely that the distribution of max reliable performance after bin-sort is exactly the same performance distribution the market wants.
If there is a larger market for 1.8GHz CPUs that output from bin-sort into the 1.8GHz max bin then you mark down some 2.0GHz parts.
Also note that the bin-sort is done at max rated temperature if the OCer keeps his die at a lower temp then it will likely run stable at higher speeds.
Coherence with respect to lasers mean that the emitted photons are in phase with each other, not that the beam is narrow.
No amount of optics can make an uncoherent beam coherent.
There are laser leds availible though.
you seem to primarily focus on shortcomings in the GUIs of the tools. You should realise that the GUI is not the primary UI of these tools. Practcally all EDA tools are script based (usually tcl) and anyone who use them for real will hardly ever use the GUI.
Performance and quality of results are much more important than GUI niceties.
As for the price, I think you left out a zero. While there are a few tools that costs as little as $10000, prices of $100000-$400000 are not uncommon.
The bitstream in SACD is the output of a pretty simplistic delta sigma modulator. (Moden audio ADCs use multibit delta sigma modulators).
... oops... we have done that since last world war and patenting this now would be difficult. Enter SACD: so silly we can patent it.
The fuction of a DS modulator is to shape the quantification nose such that it occurs outside the useful band. (in this case up to 20KHz). The 120dB dynamic range figure for SACD is only valid for DC. At the upper end of the audio spectrum it is no better or less than that of an ordinary CD.
Storing the raw output of the DS modulator strikes me as extremely silly as you will use most of your bits to store unwanted HF noise.
The only sensible thing is to filter the output and just store the information, but
The most significant advantage with using bluetooth is the marketing value of bluetooth and the fact that 2.4GHz devices may be sold all over the world. Other ISM bands differ i different regions.
There is also a potential benefit for the consumer that they might use a common reciever to hook up several bluetooth devices, I doubt if this advantage will be particularly significat in this product's lifetime though.
The price is naturally set to what logitech thinks the market is willing to pay, however with regard to your comment: Remember that a baseband controller does not a bluetooth device make. You also need the housing, RF tranciever and antenna. Which will propably drive total parts cost up towards $10-15. Considering that devices costing at retail around $30 will typically have to keep parts cost below $3 (if it is a high volume device), you'd expect a higher price on this device.
Some DSL modems have integrated routers. (Like my ISPs Cisco 677i)
That's what I thought till I went to Best Buy:
6 foot digital coax - $13 [bestbuy.com]. I actually remember paying $8 or $9 at the store but that was a while ago. Sure beats Circuit City, where the mofo tried to sell me a $40 digital cable. Ha!
You've been had. Digital coax cable is just regular 75 ohm cable with RCA jacks (though the tolerances are so wide you could also use a rusy coathanger).
This happens to be the same spec as for composite video. Chanses are that you have a pile of these lying around as they tend to come bundled with just about any piece of AV equipment. If not you should be able to pick them up for $2-6.
Opticals are less commonly bundled, but should be possible to find for around $6-8.
I have yet to see a universal remote that actualy:
A: Was universal
Not seen any ir based remote my pronto can't handle yet.
B: Did not take a universally large amount of time to setup.
That depends on what you mean by large. A pronto is configured on a computer so that speds things up a great deal.
And quite frankly I should not need a 30 button remote for just my DVD player. This is why I only view DVDs on my computer, faaar easier, don't have to switch around audio and video inputs until hell freezes over, then select the proper audio decompression scheme, then select the proper surround sound scheme, and THEN sit down and 'enjoy' the movie, and then have the honor of switching all that shit BACK to watch regular TV.
Or do is I do: have a big button that says DVD on the remote, which when pressed selects correct input on the TV and amp, then reconfigures the remote display for DVD playback control. My amp is five years old, but even that is able to correctly autoselect decoding, what kind of archaic hardware have you been using?
No thank you. . . . I can pop a DVD in my computer's drive and it starts playing, and when it is done I take it out, close the program, and I am done. End.
Funny.. After several hours of configuring DVD playback software on a PC I found that the playback software wasn't able not to reformat anamorphic material. Since the videoencoder was unable to sync to 16:9 square pixel modes (internal videoencoders in gfx cards does not have component outputs, which I require). End result was that the PC based system was unable to output 16:9 anamorphic pictures, resulting in significant image degradation.
And don't even get e started on the general unreliability and unfriendlyness on PC surround sound systems. Most of the time, it seems they assume you want some strange effects applied, or they refuse to decode at all. In contrast in my regular DVD setup i just have a regulat 75 ohm cable from the digital out of the DVD to the DVD s/pdif input of the amp, the rest just works.
A high enough bitrate will be impossible to tell apart from an analogue source, sure. But bitrates still make things sound a lot better. The best way to prove this is to get you go to a place that sells sound systems that can handle Super Audio CDs [superaudio-cd.com]. When I did this they played me two recordings of a guitar concert, one regular CD (44.1kHz, 16-bit), the other a SACD (~2.8MHz, 1-bit). None of the other settings were changed. The difference is startling.
That's because the two are mixed differently so you should hear a difference. (Yup. different mixes same disc.)
The oly real reason that SACD exist is that sony wanted to grab a slice of the audio on DVD market. An to really make som cash you need to control the standards. Unfortunately for sony the reasonable way to do things were allready well known (store PCM), and they needed somthing novel to patent.
Thus were born DSD encoding (as is used on on SACD). The fact of the matter is that DSD encodes far less information than a similar bitrate PCM stream (SACD is comparable with CDDA in fidelity) as most of the signal energy is spent in storing noise. (Take a look at the output of a delta sigma noise shaping modulator and you will see what I mean).
You can of cource not actually hear this as CDDA allready goes well beyond what is humanly perceptible. Though as SACD mandates a single bit encoding it may be possible to create pathological signals which will sound markedly worse in SACD that what might be possible on CDDA. (Single bit SD conversion has some problems with dithering)
> With the primary feature that you can play and control your xbox from literally anywhere in the world.
No, with the primary feature that they can play and control your xbox from literally anywhere in the world...
Given MS security track record, it actually means anyone can play and control your xbox (with the possible exception of you).
Unfortunately the xst synthesis software that xilinx provides is next to useless. If you do your own optimizations, then fine. If you rely on the synthesis software to optimize (and quite frankly handcrafting logic optimizations isn't my idea of fun) then you won't get very good results.
Xst isn't terribly compatible with regular synthesizable VHDL either. Expect some revriting.
As for fitting a cpu core on a fpga: Sure cpu cores aren't particularly big (even on state of the art designs, the die area is largely used for cache rather than core.)
As for pipeling: Sure you can get it up to a 100 MHz or so, but pipelining incurs penalties. You can very easily be bitten by data dependencies.
As for size, we are working on a virtex II 6000, and it can barely fit a dprototype of a design which will occupy approx 4mm^2 of silicon area on the final 0.18um asic (granted the design would have been done somwhat differently if we actually targeted the fpga)
Such cards do exist. They generally cost at least a few thousand dollars though.
Also don't expect a fpga based card do outperform a dedicated circuit. Youll need an order of magnitude (at least) more silicon area to make a circuit on an fpga than on an asic, and you can never hope to match the speed.
Furthermore you will need appropiate software to synthesize and run place and route on the fpga. These generally cost from around $10000 each, Though prices are negotiable. If you can manage with less you might be able to make do with the vendor provided synthesis software, but don't expect good results. Synplicity or leonardo spectrum (to be replaced with Precision Synthesis) are the good choices.
A modchip is usually a PIC [robotbooks.com] or ASIC [techtarget.com] programmed/designed to be used as a hardware "patch" for mass-produced hardware.
I seriously doubt anyone have made the investment of doing a asic of a modchip.
Considering that even a very simple design will cost you several $100K, I doubt if the mod-chip-makers have that kind of funds or are able to recover such costs (not to mention the difficulty of getting a design house to accept such a low-income, high-risk job)
More likely candidates are flashable microcontrollers (not just PICs, though those are very popular) or FPGAa.
Huh? Doesn't
As long as your chip is mostly digital, then yes it might.
However you must evaluate if the longer design time, increased mask costs and potentially higher tool costs (timing closure is a bitch on
As for circuits with analog components. These don't nearly shrink as much as digital (indeed they often grow due to the exotic solutions swhich might be needed) with smaller processes.
The primary obstacle for continuing develompment on our current path will likely not be technological but rather financial.
New fabs are increasing in cost at a dramatic rate, unless the semiconductor market increases it's growthrate substantially we'll likely see that while technologically possible some next stage development of CMOS will be economically infeasible as a fab won't be able to recover the cost of building it over it's lifetime.
We are not there yet, and not likely to get there for another ten years, but if present developments continue we will get there some 10-20 years from now.