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#1
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Affordable way for 1MHz - 4MHz capture and analysis??
Anyone have a suggestion for capure and analysis that does not involve
thousands of dollars? |
#2
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Affordable way for 1MHz - 4MHz capture and analysis??
what do you want to capture, and what are you analyzing for?? there is a
system that uses a vcr to capture a fairly wide section of spectrum. its too early to remember the name but someone can probably point you to the source. wrote in message ups.com... Anyone have a suggestion for capure and analysis that does not involve thousands of dollars? |
#3
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Affordable way for 1MHz - 4MHz capture and analysis??
A fast A/D front end on a PC, sampling at a minimum of 8MHz. Use the PC
as a DSP engine. I suspect that these would be available as a plug in PCI card... You can get an idea of what this is about by the plethora of sound card based analysis systems now available (with a max sample rate of 44kHz or thereabouts. Depending what you are doing and are real stingy a computer controlled HF receiver and the soundcard interface might do it for you too. Wanna be a bit more specific of your requirements and application? Cheers Bob VK2YQA wrote: Anyone have a suggestion for capure and analysis that does not involve thousands of dollars? |
#4
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Affordable way for 1MHz - 4MHz capture and analysis??
Specifically, the application is one which uses a HAM radio transciever
utilizing approx 20W-100W power and a Class E transmitter to drive data signals and power from an external coil to a series of smaller receiver coils which are implanted in biological tissue for biomedical application. I have to police/enforce the research personnel to ensure limits regarding std practices are not exceeded in regards to duration and length of RF exposure fothe patient. Of course I need to do this independently, because in this situation relying on their "good word" or verbal agreement isn't sufficient. I have to be able to be able to 1.) determine if there is a 570Hz to 4MHz signal present, and 2.) determine if it is encoded or modulated to carry the power and data signals. Not up my alley exactly, but I need to get it done. If there is an expansion card or USB interface device for PC, that would be preferable to aquiring an entire HAM rig. Any help appreciated. - Lars Bob Bob wrote: A fast A/D front end on a PC, sampling at a minimum of 8MHz. Use the PC as a DSP engine. I suspect that these would be available as a plug in PCI card... You can get an idea of what this is about by the plethora of sound card based analysis systems now available (with a max sample rate of 44kHz or thereabouts. Depending what you are doing and are real stingy a computer controlled HF receiver and the soundcard interface might do it for you too. Wanna be a bit more specific of your requirements and application? Cheers Bob VK2YQA wrote: Anyone have a suggestion for capure and analysis that does not involve thousands of dollars? |
#5
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Affordable way for 1MHz - 4MHz capture and analysis??
i wouldn't touch something like this with a ham tranceiver. not enough
control or calibration. also, now you are talking of 2 different things. a transmitter that is sending the data/power, and your need to monitor for the presence of a signal independently. for monitoring for the presence of a signal across a bandwidth like that (really 570hz or is that 570khz??) you need something like a spectrum analyzer with an appropriate wide band antenna, go check with some emi testing labs for the type of equipment they use. you will quickly learn that unless you are doing this in a shielded room there are LOTS of signals in that range that will show up. you also need to better state your requirements... 'duration and length' of exposure are the same thing and do not describe the whole problem. you must also measure the field strength (probably at a couple of locations) and frequency in addition to time. it sounds like you are not familiar enough with the terminology, equipment, or methods, to take on such a job that could be related to safety... get professional rf safety help NOW or you may need a professional lawyer in the future. wrote in message ups.com... Specifically, the application is one which uses a HAM radio transciever utilizing approx 20W-100W power and a Class E transmitter to drive data signals and power from an external coil to a series of smaller receiver coils which are implanted in biological tissue for biomedical application. I have to police/enforce the research personnel to ensure limits regarding std practices are not exceeded in regards to duration and length of RF exposure fothe patient. Of course I need to do this independently, because in this situation relying on their "good word" or verbal agreement isn't sufficient. I have to be able to be able to 1.) determine if there is a 570Hz to 4MHz signal present, and 2.) determine if it is encoded or modulated to carry the power and data signals. Not up my alley exactly, but I need to get it done. If there is an expansion card or USB interface device for PC, that would be preferable to aquiring an entire HAM rig. Any help appreciated. - Lars Bob Bob wrote: A fast A/D front end on a PC, sampling at a minimum of 8MHz. Use the PC as a DSP engine. I suspect that these would be available as a plug in PCI card... You can get an idea of what this is about by the plethora of sound card based analysis systems now available (with a max sample rate of 44kHz or thereabouts. Depending what you are doing and are real stingy a computer controlled HF receiver and the soundcard interface might do it for you too. Wanna be a bit more specific of your requirements and application? Cheers Bob VK2YQA wrote: Anyone have a suggestion for capure and analysis that does not involve thousands of dollars? |
#6
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Affordable way for 1MHz - 4MHz capture and analysis??
This looks like an interesting project! Not quite what I was thinking in
my original answer. I think your requirement is a lot simpler and cheaper. A yes no indicator for RF between 570Hz and 4Mhz should be relatively easy, especially if it is a large signal in comparison to the ambient level. You could probably do it with a band pass filter network, a few transistors and some kind of display device (eg a LED). Some sensitivity calibratation over the freq range will need doing and maybe a subsequent adjustment to the BPF. Determining if it is encoded depends on how it is encoded. If it creates pulses of a known PRF then a simple AM receiver to detect the envelope, followed by whatever ever band pass at the PRF and a subsequent display device. I cant comment on this further without knowing how you modulate. Both circuits could be mounted in a box with an "RF detected" and "Modulated signal detected" LED along with a resetable timer. You are talking maybe $30 worth of parts! Note that you will need to test its susceptability to other RF in the area so it doesnt give false readings. One assumes you want to log the above events? For that a PC can be used for with a simple low rate data acquisition module or even via the parallel port pins. As horrible as it sounds using an old clunker and a DOS version with debug will allow you to poll the printer port and print a report on completion. You can also do it with the normal tools in a current Linux versions. I think software would need to be written for a Windows environment. Probably already exists as GPL. Shd be pretty simple to write though if not. The above assumes you dont need to measure the actual exposure level.. You might be interested to know that back in the early 1980's I was involved in medical ultrasound. Most of our products were for imaging and doppler. We were however developing a higher energy device for focussed heating on cancerous etc areas. The initial tests were done with a beefed up transducer (about 50mm dia a 5mm thick) in a water bath and excited with an old Yaesu FT101B transceiver on about 3.6MHz! It was impressive to watch it boiling the surface of the water. It looked like a 360 degree waterfall.. If you want to go down the separate radio and PC device have a look at the Winradio (or similar) boxes. They use a PC as control and display for an external box with an RS232 and antenna port on it. Dont know about the software side of this though. Cheers Bob VK2YQA wrote: Specifically, the application is one which uses a HAM radio transciever utilizing approx 20W-100W power and a Class E transmitter to drive data signals and power from an external coil to a series of smaller receiver coils which are implanted in biological tissue for biomedical application. I have to police/enforce the research personnel to ensure limits regarding std practices are not exceeded in regards to duration and length of RF exposure fothe patient. Of course I need to do this independently, because in this situation relying on their "good word" or verbal agreement isn't sufficient. I have to be able to be able to 1.) determine if there is a 570Hz to 4MHz signal present, and 2.) determine if it is encoded or modulated to carry the power and data signals. Not up my alley exactly, but I need to get it done. If there is an expansion card or USB interface device for PC, that would be preferable to aquiring an entire HAM rig. Any help appreciated. - Lars |
#7
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Affordable way for 1MHz - 4MHz capture and analysis??
Bob Bob, you are outstanding! The Winradio is actually a capable and
affordable solution. From the specs, it looks like it will fit the bill, and the fact that they have a Linux version is great. Take care. -Lars Bob Bob wrote: This looks like an interesting project! Not quite what I was thinking in my original answer. I think your requirement is a lot simpler and cheaper. A yes no indicator for RF between 570Hz and 4Mhz should be relatively easy, especially if it is a large signal in comparison to the ambient level. You could probably do it with a band pass filter network, a few transistors and some kind of display device (eg a LED). Some sensitivity calibratation over the freq range will need doing and maybe a subsequent adjustment to the BPF. Determining if it is encoded depends on how it is encoded. If it creates pulses of a known PRF then a simple AM receiver to detect the envelope, followed by whatever ever band pass at the PRF and a subsequent display device. I cant comment on this further without knowing how you modulate. Both circuits could be mounted in a box with an "RF detected" and "Modulated signal detected" LED along with a resetable timer. You are talking maybe $30 worth of parts! Note that you will need to test its susceptability to other RF in the area so it doesnt give false readings. One assumes you want to log the above events? For that a PC can be used for with a simple low rate data acquisition module or even via the parallel port pins. As horrible as it sounds using an old clunker and a DOS version with debug will allow you to poll the printer port and print a report on completion. You can also do it with the normal tools in a current Linux versions. I think software would need to be written for a Windows environment. Probably already exists as GPL. Shd be pretty simple to write though if not. The above assumes you dont need to measure the actual exposure level.. You might be interested to know that back in the early 1980's I was involved in medical ultrasound. Most of our products were for imaging and doppler. We were however developing a higher energy device for focussed heating on cancerous etc areas. The initial tests were done with a beefed up transducer (about 50mm dia a 5mm thick) in a water bath and excited with an old Yaesu FT101B transceiver on about 3.6MHz! It was impressive to watch it boiling the surface of the water. It looked like a 360 degree waterfall.. If you want to go down the separate radio and PC device have a look at the Winradio (or similar) boxes. They use a PC as control and display for an external box with an RS232 and antenna port on it. Dont know about the software side of this though. Cheers Bob VK2YQA wrote: Specifically, the application is one which uses a HAM radio transciever utilizing approx 20W-100W power and a Class E transmitter to drive data signals and power from an external coil to a series of smaller receiver coils which are implanted in biological tissue for biomedical application. I have to police/enforce the research personnel to ensure limits regarding std practices are not exceeded in regards to duration and length of RF exposure fothe patient. Of course I need to do this independently, because in this situation relying on their "good word" or verbal agreement isn't sufficient. I have to be able to be able to 1.) determine if there is a 570Hz to 4MHz signal present, and 2.) determine if it is encoded or modulated to carry the power and data signals. Not up my alley exactly, but I need to get it done. If there is an expansion card or USB interface device for PC, that would be preferable to aquiring an entire HAM rig. Any help appreciated. - Lars |
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