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How can I record RF?
Communication - 2 Battery Powered Circuits, 1 Conductor, no common groundImplementing a network of RF receiver/transmittersMusic through RFhigh frequency op amp for Arduino frequency counterHow to conduct “Transient Power” measurement according to ETSI EN 300 220-1 (v2.4.1)?Simple AM radio - how to modify it so it can work without ferrite rod antenna?Can anything be done to shield a record turntable from picking up unwanted radio transmissions?Does the feed line contribute to the function of a PCB patch antenna?How to go about decoding baseband from RF?
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;
$begingroup$
For audio I can use just sound card, plus OS api to record any signal from 20 hz (below that's blocked via capacitor) to 96khz(that's half of max samplerate).
But what if I just want to go higher? As high as it possible!
How far could I go and what PC hardware should I use, in order to sample that signals?
For example, I want to record broadband signal, and do FFT, to see "what's happenin here?"
how this was even recorded? 
rf radio software-defined-radio
asked Jun 2 at 8:53
xakepp35xakepp35
23210
$endgroup$
|
show 6 more comments
$begingroup$
For audio I can use just sound card, plus OS api to record any signal from 20 hz (below that's blocked via capacitor) to 96khz(that's half of max samplerate).
But what if I just want to go higher? As high as it possible!
How far could I go and what PC hardware should I use, in order to sample that signals?
For example, I want to record broadband signal, and do FFT, to see "what's happenin here?"
how this was even recorded?
rf radio software-defined-radio
asked Jun 2 at 8:53
xakepp35xakepp35
23210
$endgroup$
$begingroup$
Probably with a spectrum analyzer.
$endgroup$
– Oldfart
Jun 2 at 8:55
$begingroup$
@Oldfart my goal is to do signal recording (with a goal to be bit-perfect, as close to original, as possible). That signal representation must end up in PC RAM and sampling frequency must be - from DC to "as high as ever possible". What is typical solution?
$endgroup$
– xakepp35
Jun 2 at 8:57
2
$begingroup$
Get yourself a very high speed ADC (or multiple ADC's) and a lot of memory. Going up to 3GHz would require vast RF experience. I would not like to try....
$endgroup$
– Oldfart
Jun 2 at 8:59
$begingroup$
@Oldfart to the fun, the question ultimately is.. how do you typically "solder" x-pin ADC chip to the PCI-E bus?
$endgroup$
– xakepp35
Jun 2 at 9:02
$begingroup$
@Oldfart is a 3ghz a cap? how far could the recording go on a decent hardware, and what is that hardware? yes, i do understand, that recording could require 3gsps, but could we go higher, to saturate x16 pci-e bus bandwidth?
$endgroup$
– xakepp35
Jun 2 at 9:09
|
show 6 more comments
$begingroup$
For audio I can use just sound card, plus OS api to record any signal from 20 hz (below that's blocked via capacitor) to 96khz(that's half of max samplerate).
But what if I just want to go higher? As high as it possible!
How far could I go and what PC hardware should I use, in order to sample that signals?
For example, I want to record broadband signal, and do FFT, to see "what's happenin here?"
how this was even recorded?
rf radio software-defined-radio
asked Jun 2 at 8:53
xakepp35xakepp35
23210
$endgroup$
For audio I can use just sound card, plus OS api to record any signal from 20 hz (below that's blocked via capacitor) to 96khz(that's half of max samplerate).
But what if I just want to go higher? As high as it possible!
How far could I go and what PC hardware should I use, in order to sample that signals?
For example, I want to record broadband signal, and do FFT, to see "what's happenin here?"
how this was even recorded?
rf radio software-defined-radio
rf radio software-defined-radio
asked Jun 2 at 8:53
xakepp35xakepp35
23210
asked Jun 2 at 8:53
xakepp35xakepp35
23210
asked Jun 2 at 8:53
xakepp35xakepp35
23210
asked Jun 2 at 8:53
xakepp35xakepp35
23210
asked Jun 2 at 8:53
xakepp35xakepp35
23210
23210
$begingroup$
Probably with a spectrum analyzer.
$endgroup$
– Oldfart
Jun 2 at 8:55
$begingroup$
@Oldfart my goal is to do signal recording (with a goal to be bit-perfect, as close to original, as possible). That signal representation must end up in PC RAM and sampling frequency must be - from DC to "as high as ever possible". What is typical solution?
$endgroup$
– xakepp35
Jun 2 at 8:57
2
$begingroup$
Get yourself a very high speed ADC (or multiple ADC's) and a lot of memory. Going up to 3GHz would require vast RF experience. I would not like to try....
$endgroup$
– Oldfart
Jun 2 at 8:59
$begingroup$
@Oldfart to the fun, the question ultimately is.. how do you typically "solder" x-pin ADC chip to the PCI-E bus?
$endgroup$
– xakepp35
Jun 2 at 9:02
$begingroup$
@Oldfart is a 3ghz a cap? how far could the recording go on a decent hardware, and what is that hardware? yes, i do understand, that recording could require 3gsps, but could we go higher, to saturate x16 pci-e bus bandwidth?
$endgroup$
– xakepp35
Jun 2 at 9:09
|
show 6 more comments
$begingroup$
Probably with a spectrum analyzer.
$endgroup$
– Oldfart
Jun 2 at 8:55
$begingroup$
@Oldfart my goal is to do signal recording (with a goal to be bit-perfect, as close to original, as possible). That signal representation must end up in PC RAM and sampling frequency must be - from DC to "as high as ever possible". What is typical solution?
$endgroup$
– xakepp35
Jun 2 at 8:57
2
$begingroup$
Get yourself a very high speed ADC (or multiple ADC's) and a lot of memory. Going up to 3GHz would require vast RF experience. I would not like to try....
$endgroup$
– Oldfart
Jun 2 at 8:59
$begingroup$
@Oldfart to the fun, the question ultimately is.. how do you typically "solder" x-pin ADC chip to the PCI-E bus?
$endgroup$
– xakepp35
Jun 2 at 9:02
$begingroup$
@Oldfart is a 3ghz a cap? how far could the recording go on a decent hardware, and what is that hardware? yes, i do understand, that recording could require 3gsps, but could we go higher, to saturate x16 pci-e bus bandwidth?
$endgroup$
– xakepp35
Jun 2 at 9:09
$begingroup$
Probably with a spectrum analyzer.
$endgroup$
– Oldfart
Jun 2 at 8:55
$begingroup$
Probably with a spectrum analyzer.
$endgroup$
– Oldfart
Jun 2 at 8:55
$begingroup$
@Oldfart my goal is to do signal recording (with a goal to be bit-perfect, as close to original, as possible). That signal representation must end up in PC RAM and sampling frequency must be - from DC to "as high as ever possible". What is typical solution?
$endgroup$
– xakepp35
Jun 2 at 8:57
$begingroup$
@Oldfart my goal is to do signal recording (with a goal to be bit-perfect, as close to original, as possible). That signal representation must end up in PC RAM and sampling frequency must be - from DC to "as high as ever possible". What is typical solution?
$endgroup$
– xakepp35
Jun 2 at 8:57
2
2
$begingroup$
Get yourself a very high speed ADC (or multiple ADC's) and a lot of memory. Going up to 3GHz would require vast RF experience. I would not like to try....
$endgroup$
– Oldfart
Jun 2 at 8:59
$begingroup$
Get yourself a very high speed ADC (or multiple ADC's) and a lot of memory. Going up to 3GHz would require vast RF experience. I would not like to try....
$endgroup$
– Oldfart
Jun 2 at 8:59
$begingroup$
@Oldfart to the fun, the question ultimately is.. how do you typically "solder" x-pin ADC chip to the PCI-E bus?
$endgroup$
– xakepp35
Jun 2 at 9:02
$begingroup$
@Oldfart to the fun, the question ultimately is.. how do you typically "solder" x-pin ADC chip to the PCI-E bus?
$endgroup$
– xakepp35
Jun 2 at 9:02
$begingroup$
@Oldfart is a 3ghz a cap? how far could the recording go on a decent hardware, and what is that hardware? yes, i do understand, that recording could require 3gsps, but could we go higher, to saturate x16 pci-e bus bandwidth?
$endgroup$
– xakepp35
Jun 2 at 9:09
$begingroup$
@Oldfart is a 3ghz a cap? how far could the recording go on a decent hardware, and what is that hardware? yes, i do understand, that recording could require 3gsps, but could we go higher, to saturate x16 pci-e bus bandwidth?
$endgroup$
– xakepp35
Jun 2 at 9:09
|
show 6 more comments
3 Answers
3
active
oldest
votes
$begingroup$
You would use an RF spectrum analyser.
You can also use a software defined radio module and something like GNU Radio to capture and analyse the signals.
The GNU Radio Wiki lists compatible hardware. Much of it is USB-based, some network-based.
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
answered Jun 2 at 9:00
JREJRE
26k64886
$endgroup$
$begingroup$
How could you input the data to the computer memory? I know about gnu radio DSP, thanks. I just want to get that signal, and sound card (that connects to PCI-E bus) just dont allow to go higher than 192k samplerate!
$endgroup$
– xakepp35
Jun 2 at 9:04
$begingroup$
USB cannot stream many gsps, i think it have to be pci-e based in first place!~
$endgroup$
– xakepp35
Jun 2 at 9:09
2
$begingroup$
There's also PCI-e hardware. But, you can't process it at full speed, any way. You will be hard pressed (read "can't do it with a standard PC") to merely stream gigasamples per second to a harddrive. Professional systems capture to their own (specially built) RAM, then deliver it to PCs or recording systems at a much lower speed. The amount of data you can record is limited by the capture RAM and the recording speed.
$endgroup$
– JRE
Jun 2 at 9:13
2
$begingroup$
A spectrum analyzer doesn't record phase information about the different frequency components, so its data is not sufficient to reconstruct the time domain signal that was its input. If the SA uses a sampling technique like most do now, it's possible the original sampled data could be stored and uploaded to a PC, but I don't know of any SA that actually provides such a function.
$endgroup$
– The Photon
Jun 2 at 13:52
1
$begingroup$
Also, for both the SA and SDR solutions, there may be analog downmixing done before the signal is sampled, which could complicate recovering the time domain waveform from the sample data.
$endgroup$
– The Photon
Jun 2 at 13:53
|
show 4 more comments
$begingroup$
If your goal is to generate the plot shown in your question, the JRE is correct, you would use a spectrum analyzer (SA). In fact, with a spectrum analyzer, the data you'd get would be essentially the plot you showed, and you wouldn't need to do any post-processing to get it.
But, you'll notice that the plot doesn't show any phase information about the signal at different frequencies. And an SA does not typically store phase information. So if there is other processing you want to do that requires the phase information, or requires reconstructing the time-domain waveform of the signal you measured, then an SA will not do what you want.
You can buy a digital storage oscilloscope with bandwidth up to over 100 GHz (and sampling rate over 250 GHz). This would allow you to do what you specifically asked for, Take the FFT of the data to get a spectrogram, and to do it for signals up to ~100 GHz. However you must be prepared to spend quite a lot of money to get this capability. AFAIK these scopes retail in the ~$1 million range at the high end.
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
$endgroup$
add a comment |
$begingroup$
To see what is happening, you'll need to record the I+Q information of each signal.
This lets you examine the modulation (amplitude, phase, frequency, frequency sweeping, phase-ramps, pseudo-random-behaviors) of each signal.
For such as 256-QAM (a rather busy signal), you will need much more information than just the time of zero-crossings. To detect (or make observable) various circuit flaws,
such as intra-pulse ringing that the antenna itself did not filter out, you'll need lots of bandwidth. This is in conflict with the broadband thermal noise of a 3GHz unfiltered input.
Additionally, to handle 50dB dynamic range (-12dBxx to -62dBx) you'll need another 50/6 = 8 bits of ADC resolution.
Fundamentally, the broadband ADC noise floors (even if 50 ohm system) do not permit digitizing AT THE ANTENNA, and you will use PreAmplifiers. Since DC_3GHz amplifiers with low noise figure (the noise density, factoring in the Zsource) are expensive and prone to intermodulation between the weak RF and the strong RF, people tend to implement narrow-band monitoring systems for RF.
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
$endgroup$
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
You would use an RF spectrum analyser.
You can also use a software defined radio module and something like GNU Radio to capture and analyse the signals.
The GNU Radio Wiki lists compatible hardware. Much of it is USB-based, some network-based.
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
answered Jun 2 at 9:00
JREJRE
26k64886
$endgroup$
$begingroup$
How could you input the data to the computer memory? I know about gnu radio DSP, thanks. I just want to get that signal, and sound card (that connects to PCI-E bus) just dont allow to go higher than 192k samplerate!
$endgroup$
– xakepp35
Jun 2 at 9:04
$begingroup$
USB cannot stream many gsps, i think it have to be pci-e based in first place!~
$endgroup$
– xakepp35
Jun 2 at 9:09
2
$begingroup$
There's also PCI-e hardware. But, you can't process it at full speed, any way. You will be hard pressed (read "can't do it with a standard PC") to merely stream gigasamples per second to a harddrive. Professional systems capture to their own (specially built) RAM, then deliver it to PCs or recording systems at a much lower speed. The amount of data you can record is limited by the capture RAM and the recording speed.
$endgroup$
– JRE
Jun 2 at 9:13
2
$begingroup$
A spectrum analyzer doesn't record phase information about the different frequency components, so its data is not sufficient to reconstruct the time domain signal that was its input. If the SA uses a sampling technique like most do now, it's possible the original sampled data could be stored and uploaded to a PC, but I don't know of any SA that actually provides such a function.
$endgroup$
– The Photon
Jun 2 at 13:52
1
$begingroup$
Also, for both the SA and SDR solutions, there may be analog downmixing done before the signal is sampled, which could complicate recovering the time domain waveform from the sample data.
$endgroup$
– The Photon
Jun 2 at 13:53
|
show 4 more comments
$begingroup$
You would use an RF spectrum analyser.
You can also use a software defined radio module and something like GNU Radio to capture and analyse the signals.
The GNU Radio Wiki lists compatible hardware. Much of it is USB-based, some network-based.
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
answered Jun 2 at 9:00
JREJRE
26k64886
$endgroup$
$begingroup$
How could you input the data to the computer memory? I know about gnu radio DSP, thanks. I just want to get that signal, and sound card (that connects to PCI-E bus) just dont allow to go higher than 192k samplerate!
$endgroup$
– xakepp35
Jun 2 at 9:04
$begingroup$
USB cannot stream many gsps, i think it have to be pci-e based in first place!~
$endgroup$
– xakepp35
Jun 2 at 9:09
2
$begingroup$
There's also PCI-e hardware. But, you can't process it at full speed, any way. You will be hard pressed (read "can't do it with a standard PC") to merely stream gigasamples per second to a harddrive. Professional systems capture to their own (specially built) RAM, then deliver it to PCs or recording systems at a much lower speed. The amount of data you can record is limited by the capture RAM and the recording speed.
$endgroup$
– JRE
Jun 2 at 9:13
2
$begingroup$
A spectrum analyzer doesn't record phase information about the different frequency components, so its data is not sufficient to reconstruct the time domain signal that was its input. If the SA uses a sampling technique like most do now, it's possible the original sampled data could be stored and uploaded to a PC, but I don't know of any SA that actually provides such a function.
$endgroup$
– The Photon
Jun 2 at 13:52
1
$begingroup$
Also, for both the SA and SDR solutions, there may be analog downmixing done before the signal is sampled, which could complicate recovering the time domain waveform from the sample data.
$endgroup$
– The Photon
Jun 2 at 13:53
|
show 4 more comments
$begingroup$
You would use an RF spectrum analyser.
You can also use a software defined radio module and something like GNU Radio to capture and analyse the signals.
The GNU Radio Wiki lists compatible hardware. Much of it is USB-based, some network-based.
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
answered Jun 2 at 9:00
JREJRE
26k64886
$endgroup$
You would use an RF spectrum analyser.
You can also use a software defined radio module and something like GNU Radio to capture and analyse the signals.
The GNU Radio Wiki lists compatible hardware. Much of it is USB-based, some network-based.
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
answered Jun 2 at 9:00
JREJRE
26k64886
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
edited Jun 2 at 9:55
Marcus Müller
37.3k364104
37.3k364104
answered Jun 2 at 9:00
JREJRE
26k64886
answered Jun 2 at 9:00
JREJRE
26k64886
answered Jun 2 at 9:00
JREJRE
26k64886
26k64886
$begingroup$
How could you input the data to the computer memory? I know about gnu radio DSP, thanks. I just want to get that signal, and sound card (that connects to PCI-E bus) just dont allow to go higher than 192k samplerate!
$endgroup$
– xakepp35
Jun 2 at 9:04
$begingroup$
USB cannot stream many gsps, i think it have to be pci-e based in first place!~
$endgroup$
– xakepp35
Jun 2 at 9:09
2
$begingroup$
There's also PCI-e hardware. But, you can't process it at full speed, any way. You will be hard pressed (read "can't do it with a standard PC") to merely stream gigasamples per second to a harddrive. Professional systems capture to their own (specially built) RAM, then deliver it to PCs or recording systems at a much lower speed. The amount of data you can record is limited by the capture RAM and the recording speed.
$endgroup$
– JRE
Jun 2 at 9:13
2
$begingroup$
A spectrum analyzer doesn't record phase information about the different frequency components, so its data is not sufficient to reconstruct the time domain signal that was its input. If the SA uses a sampling technique like most do now, it's possible the original sampled data could be stored and uploaded to a PC, but I don't know of any SA that actually provides such a function.
$endgroup$
– The Photon
Jun 2 at 13:52
1
$begingroup$
Also, for both the SA and SDR solutions, there may be analog downmixing done before the signal is sampled, which could complicate recovering the time domain waveform from the sample data.
$endgroup$
– The Photon
Jun 2 at 13:53
|
show 4 more comments
$begingroup$
How could you input the data to the computer memory? I know about gnu radio DSP, thanks. I just want to get that signal, and sound card (that connects to PCI-E bus) just dont allow to go higher than 192k samplerate!
$endgroup$
– xakepp35
Jun 2 at 9:04
$begingroup$
USB cannot stream many gsps, i think it have to be pci-e based in first place!~
$endgroup$
– xakepp35
Jun 2 at 9:09
2
$begingroup$
There's also PCI-e hardware. But, you can't process it at full speed, any way. You will be hard pressed (read "can't do it with a standard PC") to merely stream gigasamples per second to a harddrive. Professional systems capture to their own (specially built) RAM, then deliver it to PCs or recording systems at a much lower speed. The amount of data you can record is limited by the capture RAM and the recording speed.
$endgroup$
– JRE
Jun 2 at 9:13
2
$begingroup$
A spectrum analyzer doesn't record phase information about the different frequency components, so its data is not sufficient to reconstruct the time domain signal that was its input. If the SA uses a sampling technique like most do now, it's possible the original sampled data could be stored and uploaded to a PC, but I don't know of any SA that actually provides such a function.
$endgroup$
– The Photon
Jun 2 at 13:52
1
$begingroup$
Also, for both the SA and SDR solutions, there may be analog downmixing done before the signal is sampled, which could complicate recovering the time domain waveform from the sample data.
$endgroup$
– The Photon
Jun 2 at 13:53
$begingroup$
How could you input the data to the computer memory? I know about gnu radio DSP, thanks. I just want to get that signal, and sound card (that connects to PCI-E bus) just dont allow to go higher than 192k samplerate!
$endgroup$
– xakepp35
Jun 2 at 9:04
$begingroup$
How could you input the data to the computer memory? I know about gnu radio DSP, thanks. I just want to get that signal, and sound card (that connects to PCI-E bus) just dont allow to go higher than 192k samplerate!
$endgroup$
– xakepp35
Jun 2 at 9:04
$begingroup$
USB cannot stream many gsps, i think it have to be pci-e based in first place!~
$endgroup$
– xakepp35
Jun 2 at 9:09
$begingroup$
USB cannot stream many gsps, i think it have to be pci-e based in first place!~
$endgroup$
– xakepp35
Jun 2 at 9:09
2
2
$begingroup$
There's also PCI-e hardware. But, you can't process it at full speed, any way. You will be hard pressed (read "can't do it with a standard PC") to merely stream gigasamples per second to a harddrive. Professional systems capture to their own (specially built) RAM, then deliver it to PCs or recording systems at a much lower speed. The amount of data you can record is limited by the capture RAM and the recording speed.
$endgroup$
– JRE
Jun 2 at 9:13
$begingroup$
There's also PCI-e hardware. But, you can't process it at full speed, any way. You will be hard pressed (read "can't do it with a standard PC") to merely stream gigasamples per second to a harddrive. Professional systems capture to their own (specially built) RAM, then deliver it to PCs or recording systems at a much lower speed. The amount of data you can record is limited by the capture RAM and the recording speed.
$endgroup$
– JRE
Jun 2 at 9:13
2
2
$begingroup$
A spectrum analyzer doesn't record phase information about the different frequency components, so its data is not sufficient to reconstruct the time domain signal that was its input. If the SA uses a sampling technique like most do now, it's possible the original sampled data could be stored and uploaded to a PC, but I don't know of any SA that actually provides such a function.
$endgroup$
– The Photon
Jun 2 at 13:52
$begingroup$
A spectrum analyzer doesn't record phase information about the different frequency components, so its data is not sufficient to reconstruct the time domain signal that was its input. If the SA uses a sampling technique like most do now, it's possible the original sampled data could be stored and uploaded to a PC, but I don't know of any SA that actually provides such a function.
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– The Photon
Jun 2 at 13:52
1
1
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Also, for both the SA and SDR solutions, there may be analog downmixing done before the signal is sampled, which could complicate recovering the time domain waveform from the sample data.
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– The Photon
Jun 2 at 13:53
$begingroup$
Also, for both the SA and SDR solutions, there may be analog downmixing done before the signal is sampled, which could complicate recovering the time domain waveform from the sample data.
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– The Photon
Jun 2 at 13:53
|
show 4 more comments
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If your goal is to generate the plot shown in your question, the JRE is correct, you would use a spectrum analyzer (SA). In fact, with a spectrum analyzer, the data you'd get would be essentially the plot you showed, and you wouldn't need to do any post-processing to get it.
But, you'll notice that the plot doesn't show any phase information about the signal at different frequencies. And an SA does not typically store phase information. So if there is other processing you want to do that requires the phase information, or requires reconstructing the time-domain waveform of the signal you measured, then an SA will not do what you want.
You can buy a digital storage oscilloscope with bandwidth up to over 100 GHz (and sampling rate over 250 GHz). This would allow you to do what you specifically asked for, Take the FFT of the data to get a spectrogram, and to do it for signals up to ~100 GHz. However you must be prepared to spend quite a lot of money to get this capability. AFAIK these scopes retail in the ~$1 million range at the high end.
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
$endgroup$
add a comment |
$begingroup$
If your goal is to generate the plot shown in your question, the JRE is correct, you would use a spectrum analyzer (SA). In fact, with a spectrum analyzer, the data you'd get would be essentially the plot you showed, and you wouldn't need to do any post-processing to get it.
But, you'll notice that the plot doesn't show any phase information about the signal at different frequencies. And an SA does not typically store phase information. So if there is other processing you want to do that requires the phase information, or requires reconstructing the time-domain waveform of the signal you measured, then an SA will not do what you want.
You can buy a digital storage oscilloscope with bandwidth up to over 100 GHz (and sampling rate over 250 GHz). This would allow you to do what you specifically asked for, Take the FFT of the data to get a spectrogram, and to do it for signals up to ~100 GHz. However you must be prepared to spend quite a lot of money to get this capability. AFAIK these scopes retail in the ~$1 million range at the high end.
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
$endgroup$
add a comment |
$begingroup$
If your goal is to generate the plot shown in your question, the JRE is correct, you would use a spectrum analyzer (SA). In fact, with a spectrum analyzer, the data you'd get would be essentially the plot you showed, and you wouldn't need to do any post-processing to get it.
But, you'll notice that the plot doesn't show any phase information about the signal at different frequencies. And an SA does not typically store phase information. So if there is other processing you want to do that requires the phase information, or requires reconstructing the time-domain waveform of the signal you measured, then an SA will not do what you want.
You can buy a digital storage oscilloscope with bandwidth up to over 100 GHz (and sampling rate over 250 GHz). This would allow you to do what you specifically asked for, Take the FFT of the data to get a spectrogram, and to do it for signals up to ~100 GHz. However you must be prepared to spend quite a lot of money to get this capability. AFAIK these scopes retail in the ~$1 million range at the high end.
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
$endgroup$
If your goal is to generate the plot shown in your question, the JRE is correct, you would use a spectrum analyzer (SA). In fact, with a spectrum analyzer, the data you'd get would be essentially the plot you showed, and you wouldn't need to do any post-processing to get it.
But, you'll notice that the plot doesn't show any phase information about the signal at different frequencies. And an SA does not typically store phase information. So if there is other processing you want to do that requires the phase information, or requires reconstructing the time-domain waveform of the signal you measured, then an SA will not do what you want.
You can buy a digital storage oscilloscope with bandwidth up to over 100 GHz (and sampling rate over 250 GHz). This would allow you to do what you specifically asked for, Take the FFT of the data to get a spectrogram, and to do it for signals up to ~100 GHz. However you must be prepared to spend quite a lot of money to get this capability. AFAIK these scopes retail in the ~$1 million range at the high end.
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
answered Jun 2 at 14:03
The PhotonThe Photon
89.8k3105209
89.8k3105209
add a comment |
add a comment |
$begingroup$
To see what is happening, you'll need to record the I+Q information of each signal.
This lets you examine the modulation (amplitude, phase, frequency, frequency sweeping, phase-ramps, pseudo-random-behaviors) of each signal.
For such as 256-QAM (a rather busy signal), you will need much more information than just the time of zero-crossings. To detect (or make observable) various circuit flaws,
such as intra-pulse ringing that the antenna itself did not filter out, you'll need lots of bandwidth. This is in conflict with the broadband thermal noise of a 3GHz unfiltered input.
Additionally, to handle 50dB dynamic range (-12dBxx to -62dBx) you'll need another 50/6 = 8 bits of ADC resolution.
Fundamentally, the broadband ADC noise floors (even if 50 ohm system) do not permit digitizing AT THE ANTENNA, and you will use PreAmplifiers. Since DC_3GHz amplifiers with low noise figure (the noise density, factoring in the Zsource) are expensive and prone to intermodulation between the weak RF and the strong RF, people tend to implement narrow-band monitoring systems for RF.
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
$endgroup$
add a comment |
$begingroup$
To see what is happening, you'll need to record the I+Q information of each signal.
This lets you examine the modulation (amplitude, phase, frequency, frequency sweeping, phase-ramps, pseudo-random-behaviors) of each signal.
For such as 256-QAM (a rather busy signal), you will need much more information than just the time of zero-crossings. To detect (or make observable) various circuit flaws,
such as intra-pulse ringing that the antenna itself did not filter out, you'll need lots of bandwidth. This is in conflict with the broadband thermal noise of a 3GHz unfiltered input.
Additionally, to handle 50dB dynamic range (-12dBxx to -62dBx) you'll need another 50/6 = 8 bits of ADC resolution.
Fundamentally, the broadband ADC noise floors (even if 50 ohm system) do not permit digitizing AT THE ANTENNA, and you will use PreAmplifiers. Since DC_3GHz amplifiers with low noise figure (the noise density, factoring in the Zsource) are expensive and prone to intermodulation between the weak RF and the strong RF, people tend to implement narrow-band monitoring systems for RF.
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
$endgroup$
add a comment |
$begingroup$
To see what is happening, you'll need to record the I+Q information of each signal.
This lets you examine the modulation (amplitude, phase, frequency, frequency sweeping, phase-ramps, pseudo-random-behaviors) of each signal.
For such as 256-QAM (a rather busy signal), you will need much more information than just the time of zero-crossings. To detect (or make observable) various circuit flaws,
such as intra-pulse ringing that the antenna itself did not filter out, you'll need lots of bandwidth. This is in conflict with the broadband thermal noise of a 3GHz unfiltered input.
Additionally, to handle 50dB dynamic range (-12dBxx to -62dBx) you'll need another 50/6 = 8 bits of ADC resolution.
Fundamentally, the broadband ADC noise floors (even if 50 ohm system) do not permit digitizing AT THE ANTENNA, and you will use PreAmplifiers. Since DC_3GHz amplifiers with low noise figure (the noise density, factoring in the Zsource) are expensive and prone to intermodulation between the weak RF and the strong RF, people tend to implement narrow-band monitoring systems for RF.
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
$endgroup$
To see what is happening, you'll need to record the I+Q information of each signal.
This lets you examine the modulation (amplitude, phase, frequency, frequency sweeping, phase-ramps, pseudo-random-behaviors) of each signal.
For such as 256-QAM (a rather busy signal), you will need much more information than just the time of zero-crossings. To detect (or make observable) various circuit flaws,
such as intra-pulse ringing that the antenna itself did not filter out, you'll need lots of bandwidth. This is in conflict with the broadband thermal noise of a 3GHz unfiltered input.
Additionally, to handle 50dB dynamic range (-12dBxx to -62dBx) you'll need another 50/6 = 8 bits of ADC resolution.
Fundamentally, the broadband ADC noise floors (even if 50 ohm system) do not permit digitizing AT THE ANTENNA, and you will use PreAmplifiers. Since DC_3GHz amplifiers with low noise figure (the noise density, factoring in the Zsource) are expensive and prone to intermodulation between the weak RF and the strong RF, people tend to implement narrow-band monitoring systems for RF.
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
answered Jun 2 at 14:56
analogsystemsrfanalogsystemsrf
17.5k2823
17.5k2823
add a comment |
add a comment |
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$begingroup$
Probably with a spectrum analyzer.
$endgroup$
– Oldfart
Jun 2 at 8:55
$begingroup$
@Oldfart my goal is to do signal recording (with a goal to be bit-perfect, as close to original, as possible). That signal representation must end up in PC RAM and sampling frequency must be - from DC to "as high as ever possible". What is typical solution?
$endgroup$
– xakepp35
Jun 2 at 8:57
2
$begingroup$
Get yourself a very high speed ADC (or multiple ADC's) and a lot of memory. Going up to 3GHz would require vast RF experience. I would not like to try....
$endgroup$
– Oldfart
Jun 2 at 8:59
$begingroup$
@Oldfart to the fun, the question ultimately is.. how do you typically "solder" x-pin ADC chip to the PCI-E bus?
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– xakepp35
Jun 2 at 9:02
$begingroup$
@Oldfart is a 3ghz a cap? how far could the recording go on a decent hardware, and what is that hardware? yes, i do understand, that recording could require 3gsps, but could we go higher, to saturate x16 pci-e bus bandwidth?
$endgroup$
– xakepp35
Jun 2 at 9:09