Re: MD: MZ-R30 vs. MZ-R37 vs. MD MS-702 vs. MZ-R90, et. al.
On 8 May 2000, Stainless Steel Rat wrote:
Sony vs. Sharp: End Search ('nuff said). When shifting character sets
(upper, lower, special), the R90 resets the letter to "A" each cycle; 702
is smart enough to remember that "n" and "N" are the same letter.
Weird. I have an MZ-R50, and it doesn't do that. Guess they introduced a
weird bug in there or something.
gopi.
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Re: MD: compression
On Wed, 3 May 2000, Stainless Steel Rat wrote: * Ralph Smeets [EMAIL PROTECTED] on Wed, 03 May 2000 | How come that I can use my GSM phone in several parts of the US? Like WDCT, it probably isn't encrypted. I see no reason why it wouldn't be encrypted, since CDMA phones in the US are encrypted. THe FCC has no problem with encrypted cellular communications. The FBI does their wiretaps at the cellular company offices, not over the air. Much simpler. gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: compression
On Wed, 3 May 2000, Stainless Steel Rat wrote: * [EMAIL PROTECTED] on Wed, 03 May 2000 | I see no reason why it wouldn't be encrypted, since CDMA phones in the US | are encrypted. According to Qualcom's CDMA FAQ, it breaks up a conversation into TCP/IP packets (the "digital encoding"), and each packet is sent on a different frequency (the "spread spectrum transmission"). There is no mention of encryption (such as 3DES) in their technology FAQ or glossary. http://www.teledotcom.com/0597/headend/tdc0597headend_algorithm.html Discussion of how weak and pathetic the encryption algorithms. Note, of course, that this means there _is_ encryption. http://www.counterpane.com/cmea-qualcomm.html http://www.wirelessreview.com/issues/1998/81101/protocol.htm I just spent less than 10 minutes searching and finding multiple independant sources that believe that cellular phones in the US are encrypted. Please do us all the courtesy of doing similar before you assert something without justification. | THe FCC has no problem with encrypted cellular communications. *cough* They approve and allocate spectrum for encrypted communications standards. Maybe they only do it grudgingly, so I shoudln't have spoken about their motives. | The FBI does their wiretaps at the cellular company offices, not over the | air. Much simpler. What does this have to do with anything? It would be the only reason that they might object to encryption? gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: compression
On Tue, 2 May 2000, Stainless Steel Rat wrote: * [EMAIL PROTECTED] on Tue, 02 May 2000 | ATRAC is an algorithm. GSM is an algorithm. MPEG is an algorithm. Algorithmic transformation. ATRAC is not a transformation (strictest definition). What you get out is the same as what you put in, just less of it. MP3 is actually two algorithms, a bitwise reduction and Huffman coding; the Huffman coding is a transformation. Now you seem to be trying to argue detailed semantics. It would perhaps be a good idea if you were to define these terms precisely, since it seems that you are in the habit of redefining terms frequently... | ...reducing data so as to require less digital bits to transmit. The | increase in carrier capacity or decrease in storage space are just side | effects; the critical reason it's considered compression is because there | are less bits needed to transmit the signal. Less bits needed to transmit the signal = effectively increasing carrier capacity. Of course. But my point is that it's called compression not because it increases carrier capacity, but because it decreases the bits. Compression refers to a specific type process rather than an effect. | You are making the same mistake over and over. You are trying to look at | analog and digital signals and claiming that because some particular way | of encoding analog signals may take up more space than another particular | way of encoding digital signals, therefore it's a form of compression. You are making the same mistake over and over. You are trying to look at audio sampling under the very strict definitions of communications rather than the more generalized definitions used by the layman. Just because laypeople such as yourself choose to use an incorrect definition is not an excuse. You also have failed to produce anybody anywhere other than yourself who believes in this definition. I know many people who fit the definition of laypeople in the digital audio field and they have all been astonished that DAC and ADC could be called "compression". I'm also not using the "communications" definition. I'm using the only definition I have ever heard expressed by any person other than yourself. Actually, I am unfamiliar with "laymen" who talk about data compression...maybe the laypeople over where you live are different? :) | Analog to digital covnersion is NOT compression. CITE A SOURCE if you are | going to continue to assert this. CD-Video. Perhaps you're confused about what "citing a source" means. Find an authoritative and reliable source that backs up your claim. I've done that for my claims, now it's your turn. Find a standards document to back up your claim. Specifically, something that says that it's compression. | Sadly, I haven't found a source that stated that ADC was not compression; | most people in the field would never even consider that as a possibility. I'm not talking about what "people in the field" think. I am talking about what everybody else thinks. "everybody else" seems to disagree with you so far. I'm not an expert in digital audio, signal processing, data compression, or any other related field. I'm a computer science major. My compression experience is limited to writing some Huffman compression code awhile back, and porting some wavelet compression source to the Newton MessagePad. NO formal training. I'm not "in the field". Please cite a source, find somebody else who agrees with you? gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: compression
On Tue, 2 May 2000, Stainless Steel Rat wrote: * Ralph Smeets [EMAIL PROTECTED] on Tue, 02 May 2000 | GSM is compressed and encrypted. And not used in the US. We have PCS, which is not encrypted. The header packets are secured using a key exchange mechanism to prevent theft of IDs. You did not read my message. I cited sources demonstrating that CDMA, used in the US, is both compressed and encrypted. The fact is, compresed and encrypted wireless cellular systems are widely used in the US. Whether this was an FCC loophole or not is irrelevant; your initial claim has been demonstrated to be incorrect. gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: compression
On Tue, 2 May 2000, Stainless Steel Rat wrote: * [EMAIL PROTECTED] on Mon, 01 May 2000 | That is absolutely false. IEEE 802.11, aka WaveLAN, aka Orinoco is a | license free 2.4GHz wireless networking system. It is licensed and | approved and used (widely) in the United States. It includes either 40 | bit or 128 bit encryption depending on the version you use. This is an interesting loophole in the FCC regs. An 802.11 packet can be considered to be clear even when what is inside the envelope is encrypted. When the regs were drafted they never considered the idea of encapsulation, or never took it seriously. I suspect the FCC was quite annoyed when they learned about 802.11 and related protocols. They're quite happy with cellular links being encrypted. Why did you claim that it was impossible to send compressed and encrypted communications when you appear to know full well that many standards used are both compressed and encrypted? Your original claim, that cellular communications couldn't be encrypted or compressed has been proven false. You may be trying to demonstrate your knowledge by describing in more detail how something works, but the fact remains that your initial claims were wrong; I'm dubious as to whether I should trust any of the other information you are so sure about. gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: compression
On Mon, 1 May 2000, Stainless Steel Rat wrote: Another example: cellular vs. digital pcs. Same absolute bandwidth. No conventional compression. Yet you can get several times more effective bandwidth with pcs on the same carrier as you can with cellular. Actually, you will find that digital cellular systems virtually universally use lossy compression for the voice. GSM for sure does, and most others I have seen do. gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: compression
On 1 May 2000, Stainless Steel Rat wrote: * [EMAIL PROTECTED] on Mon, 01 May 2000 | Actually, you will find that digital cellular systems virtually | universally use lossy compression for the voice. GSM for sure does, and | most others I have seen do. Actually, no, they don't. This comes straight from a guy who co-wrote the Sprint PCS software (he is now my co-sysmonster). The FCC does not allow You'd better talk to him some more; the information you've given so far is blatantly incorrect. Perhaps you've misunderstood him? compression or encryption; all civilian aerial broadcasts must be clear. That is absolutely false. IEEE 802.11, aka WaveLAN, aka Orinoco is a license free 2.4GHz wireless networking system. It is licensed and approved and used (widely) in the United States. It includes either 40 bit or 128 bit encryption depending on the version you use. Given that I am currently writing a driver for WaveLAN cards, I do understand the standard somewhat. When I finish the driver, I will understand the standard much more :) http://www.qualcomm.com/cda/technology/display/0,1595,,00.html Qualcomm makes phones in the US. Their phones are fully encrypted. And fully FCC approved. As a licensed radio amateur, I can assure you that I am fully allowed to send compressed data. Amateur bands are explicitly prohibited from using encryption, but that is not a limitation of all bands. The specific limitation on the amateur band is that I have to use a publicly defined encoding scheme. http://www.qualcomm.com/cdmatechnologies/products/documents/CDMADataBook.pdf Page 5 contains a description of the "variable rate vocoder". It's a rather un-technical description, but it clearly explains the fact that CDMA, a cellular standard used and approved in the US, uses lossy compression like ATRAC. The lossy compression you describe is achieved by ratcheting back the sampling frequency rate to concentrate on the baritone and tennor ranges, ignoring the bass and alto ranges entirely. The sampling rate has nothing to do with cutting off the low end of the audio spectrum. The lossy compression I was referring to was that used in GSM, the phone system used in pretty much everywhere but the US. GSM uses a perceptual acoustic lossy compression system very similar to ATRAC. I know this for a fact, having read through source code that did GSM compression. "ratcheting back"? Back from _what_? From infinite? Your suggestion that sampling rate has anything to do with the low end response of a system belies your lack of understanding. You could encode a 0.01 Hz signal digitally. The analog circuitry of your system would be unlikely to play it, but the sampling rate would have nothing to do with bottom end response, just top end. It is the same thing CD-DA sampling does. No, it's not. Efficiency is _not_ compression. Is microfiche a "compressed" form of a book? It's smaller, yes, but it is not compression. It's merely denser. Please, before you continue to make assertions, do a bit of research and cite some sources for your claims? gopi. -computer science major, radio ham, random electronics geek, etc. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: compression
On 1 May 2000, Stainless Steel Rat wrote: * "Jiawei Ye" [EMAIL PROTECTED] on Mon, 01 May 2000 | If "compression" is defined as you did (you defined CD-DA as | "compression"), no digital mobile phone system will exist in the US, | 'cause "the FCC does not allow compression or encryption" There is no One True Definition of compression. The definition of But there are many incorrect ones... compression used in the communications industry has a narrow scope. To the comms guys and the FCC, compression is an algorithmic transformation of clear data into coded data, and data loss is usually not allowed. To them, Key word there. "usually". Which would imply that it is sometimes allowed. Hmm. Also, since CDMA does lossy compression, and is allowed by the FCC, well, that would seem to suggest that the comms guys you like to talk about so much seem quite happy with lossy compression. The GSM comms guys outside the US definitely seem happy with that... "lossy compression" is an oxymoron. This is the correct definition to use when discussing communications systems, which is what I was doing. Compression was traditionally lossless because originally nobody knew how to make lossy compression systems that worked well. Originally all compression was lossless; now compression is divied into lossy and lossless. By that definition, ATRAC is not compression. But by our consensus, ATRAC is compression. We have decided that the comms definition is too narrow "our" includes professionals in the field. So I figure that we're safe in considering it a good definition. for our needs, so we use a different definition, one with a broader scope. Newer, not just different. Instead of an algorithmic transformation, compression is the process of ATRAC is an algorithm. GSM is an algorithm. MPEG is an algorithm. reducing data so as to require less space to store or less carrier capacity ...reducing data so as to require less digital bits to transmit. The increase in carrier capacity or decrease in storage space are just side effects; the critical reason it's considered compression is because there are less bits needed to transmit the signal. to transmit. By this definition, the sampling rate cutoff used by PCS and GSM is considered to be a compression scheme. You are making the same mistake over and over. You are trying to look at analog and digital signals and claiming that because some particular way of encoding analog signals may take up more space than another particular way of encoding digital signals, therefore it's a form of compression. Analog to digital covnersion is NOT compression. CITE A SOURCE if you are going to continue to assert this. Sadly, I haven't found a source that stated that ADC was not compression; most people in the field would never even consider that as a possibility. So, if you wish to continue to assert something that the rest of the list disagrees with, perhaps you could just find us somebody else who agrees with you? It's getting tiring to see you constantly making incorrect claims and arguing "I think it should be this way!". It isn't. Sorry. So, back to the original point. Is the sampling rate cutoff used by CD-DA sampling a form of lossy compression? By the very strict definition of the comms industry, no. By the very broad definition of the MD community, yes. By your incorrect extrapolation of our definition, yes. But you do appear to be the only one here who appears to believe this. I must again point out that the creators of ATRAC, and many other standards such as MPEG believe that their systems are forms of compression. If professionals in the field of data compression believe that lossy compression is still compression, you'd better have more reason to argue than "I disagree". It's amusing, it was originally suggested that I take the debate to this list so that my innacurate information would be corrected by the list members. So far it would seem that most of the corrections have been made to rat's info, and by many people other than me... gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
MD: compression
Hi, (I've been away from the MD-L for a few years, but am returning now because I'm trying to clarify some terminology...) Somebody claimed: CD-DA is compressed in a manner similar to MD: it removes bits of information that you allegedly cannot hear (which is not true). Now, as I understand it, recording at 44.1kHz and thus cutting out all audio above 22.05kHz (and having somewhat of an effect on frequencies close to that too...) simply isn't called compression. I was under the impression that "compression" (in the digital sense, not in the analog processing sense) meant taking a bit stream and reducing it. Merely using a low bit rate initially woudln't be compression since you don't "decompress" it. Anyway, I would appreciate it if anybody here could tell me if my understanding is correct or not, since nothing I have said so far has convinced him that the statement is incorrect... gopi. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
