If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#141
|
|||
|
|||
Wind/Solar Electrics ???
Where is the baseband information stored if it isn't
encoded into the sampling? "Hal Murray" wrote in message ... So, if I have a signal with a 1000 hz carrier, with a bandwidth of 50 hz, you think I can sample it at just 150 hz and get accurate reproduction? That's just wrong. No, that's the whole point of this discussion. You have to understand aliasing. The signal you want aliases down into the baseband. Your anti-aliaising filter has to get rid of all the junk you don't want. In this case it includes the baseband. Since there is no baseband signal (or other out-of-band junk) you can reconstruct the original signal. It's a common trick with software radios. You do need some extra information that doesn't go in through the A/D channel. That's the design of the system, in particular what the anti-aliasing filter lets through. Maybe the reason that this is so confusing is that you also need that info the the normal/baseband case. But since that's the normal case we don't bother mentioning it. -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. |
#142
|
|||
|
|||
Wind/Solar Electrics ???
Where is the baseband information stored if it isn't
encoded into the sampling? I'm not sure what you are asking. If you have a 1 MHz carrier with 1 KHz of bandwidth, you might do something like sample at 10 KHz so your anti-alias filter has some room to work with. Then you feed the signal into a FFT and throw away the buckets that the filter didn't get rid of. You often pick the sampling frequency so the FFT buckets (after aliasing) come out on convenient numbers. If by "baseband" you mean the raw signal between 0 and X, there isn't any information between 0 and X-tiny in a typical narrow band modulated signal. If you are doing the aliasing trick, the anti-aliasing filter has to block the baseband junk (noise) or it will get into the A/D and confuse things. It's the reverse of the "normal" anti-alias filter that gets rid of the noise above the baseband so it doesn't alias down and trash your signal. -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. |
#143
|
|||
|
|||
Wind/Solar Electrics ???
George is alive and well and full of Christmas cheer.
Merry Christmas to all and may you all have a great solar new year. Even you Wayne. wmbjk wrote: On Sun, 25 Dec 2005 17:50:50 +1100, George Ghio wrote: "George Ghio" wrote in message ... Yes this is the problem. While there are people who will tell you anything to make a sale, how do you know what you are really getting. One test is the "Modified Square Wave" test. When you hear these words you know you are dealing either with a shyster or an ignorant person who should not be selling things he does not understand. daestrom wrote: Judging from your previous posts, I think you mean when you hear "Modified *sine* wave", then you know you are dealing with shyster or an ignorant person...." A salesperson that says their unit puts out a modified *square* wave would be a sign[sic] of a knowledgable salesperson. daestrom I'll pay that. Thank you for the correction. Spent too many hours under the car, I guess. OHMYGOD! A blunder admitted! Who the hell are you and what have you done with George Ghio? Wayne PS It's in everyone's best interest that you not be found out, so don't forget to hide your pod. |
#144
|
|||
|
|||
Wind/Solar Electrics ???
You too George.
Merry Christmas to Wayne and all his socks. "George Ghio" wrote in message ... George is alive and well and full of Christmas cheer. Merry Christmas to all and may you all have a great solar new year. Even you Wayne. wmbjk wrote: On Sun, 25 Dec 2005 17:50:50 +1100, George Ghio wrote: "George Ghio" wrote in message ... Yes this is the problem. While there are people who will tell you anything to make a sale, how do you know what you are really getting. One test is the "Modified Square Wave" test. When you hear these words you know you are dealing either with a shyster or an ignorant person who should not be selling things he does not understand. daestrom wrote: Judging from your previous posts, I think you mean when you hear "Modified *sine* wave", then you know you are dealing with shyster or an ignorant person...." A salesperson that says their unit puts out a modified *square* wave would be a sign[sic] of a knowledgable salesperson. daestrom I'll pay that. Thank you for the correction. Spent too many hours under the car, I guess. OHMYGOD! A blunder admitted! Who the hell are you and what have you done with George Ghio? Wayne PS It's in everyone's best interest that you not be found out, so don't forget to hide your pod. |
#145
|
|||
|
|||
Wind/Solar Electrics ???
The point is the sampling rate has to be done at just
over double the frequency of the signal and not the bandwidth. "Hal Murray" wrote in message ... Where is the baseband information stored if it isn't encoded into the sampling? I'm not sure what you are asking. If you have a 1 MHz carrier with 1 KHz of bandwidth, you might do something like sample at 10 KHz so your anti-alias filter has some room to work with. Then you feed the signal into a FFT and throw away the buckets that the filter didn't get rid of. You often pick the sampling frequency so the FFT buckets (after aliasing) come out on convenient numbers. If by "baseband" you mean the raw signal between 0 and X, there isn't any information between 0 and X-tiny in a typical narrow band modulated signal. If you are doing the aliasing trick, the anti-aliasing filter has to block the baseband junk (noise) or it will get into the A/D and confuse things. It's the reverse of the "normal" anti-alias filter that gets rid of the noise above the baseband so it doesn't alias down and trash your signal. -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. |
#146
|
|||
|
|||
Wind/Solar Electrics ???
The point is the sampling rate has to be done at just
over double the frequency of the signal and not the bandwidth. I'm sorry that I'm not smart enough to describe it in a way that you can understand. Maybe if you google for software-radio you will find something that explains it in a way that makes sense. -- The suespammers.org mail server is located in California. So are all my other mailboxes. Please do not send unsolicited bulk e-mail or unsolicited commercial e-mail to my suespammers.org address or any of my other addresses. These are my opinions, not necessarily my employer's. I hate spam. |
#147
|
|||
|
|||
Wind/Solar Electrics ???
On Sun, 25 Dec 2005 17:50:50 +1100, George Ghio wrote:
On Sun, 25 Dec 2005 17:50:50 +1100, George Ghio top-posted: I'll pay that. Thank you for the correction. Spent too many hours under the car, I guess. Just out of curiosity, is top-posting de rigeur on the rec.ovulation.awning NG? Someone has crossposted this to sci.erectionics. desire, and the convention there is to bottom- or mid- (or interspersed- ) post. Just wondering - the clsoest I've been to aviating is I logged 4 hrs. worth of lessons in a C-150, and onec I sat in the Republic Airlines DC-9 simulator - that was a trip! My only other associations with aircarft other than as a passenter is that I worked at a place that sold little tiiny 28V 40A PSUs, and I'd rather jump out of an airplane (with a proper aprachute, of course), than try to land one. ;-) Thanks! Rich daestrom wrote: "George Ghio" wrote in message ... Yes this is the problem. While there are people who will tell you anything to make a sale, how do you know what you are really getting. One test is the "Modified Square Wave" test. When you hear these words you know you are dealing either with a shyster or an ignorant person who should not be selling things he does not understand. Judging from your previous posts, I think you mean when you hear "Modified *sine* wave", then you know you are dealing with shyster or an ignorant person...." A salesperson that says their unit puts out a modified *square* wave would be a sign[sic] of a knowledgable salesperson. daestrom |
#148
|
|||
|
|||
Wind/Solar Electrics ???
Which one do you have trouble reading?
"Rich Grise, but drunk" wrote in message news Just out of curiosity, is top-posting de rigeur on the rec.ovulation.awning NG? Someone has crossposted this to sci.erectionics. desire, and the convention there is to bottom- or mid- (or interspersed- ) post. |
#149
|
|||
|
|||
Wind/Solar Electrics ???
George Ghio wrote:
wrote: George Ghio wrote: I did build a kit inverter, once, years ago. It had a max rating of 150W, Which it met. It had a half hour rating of 0W And a surge of about 300W I'm still scratching my head over that one. Which part don't you understand I didnt seriously think you were going to stand by the above specs. Since you are, enough said. NT |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Question on 172 M electrics... (1974 Skyhawk II) | [email protected] | Piloting | 8 | April 10th 04 04:52 AM |