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#1
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Selective level meter
I'm reading the calibration section of the service manual for a spectrum
analyser, and that tells me to connect the IF output to a 'selective level meter'. I've had a google and can find lots of (mostly antique) models, but I can't seem to find anything that describes what one of these is. Am I right in guessing it's essentially a narrowband AM receiver with a power meter for the carrier? So a spectrum analyser with only one horizontal point? Are they typically more accurate than a spectrum analyser - or can I just use another analyser? Thanks Theo |
#2
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Selective level meter
Theo Markettos wrote:
I'm reading the calibration section of the service manual for a spectrum analyser, and that tells me to connect the IF output to a 'selective level meter'. I've had a google and can find lots of (mostly antique) models, but I can't seem to find anything that describes what one of these is. Am I right in guessing it's essentially a narrowband AM receiver with a power meter for the carrier? So a spectrum analyser with only one horizontal point? Are they typically more accurate than a spectrum analyser - or can I just use another analyser? Thanks Theo An audio distortion analyzer has a kind of selective meter, i.e. a voltmeter with a bandpass filter upstream. |
#3
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Selective level meter
In article ,
Theo Markettos wrote: I'm reading the calibration section of the service manual for a spectrum analyser, and that tells me to connect the IF output to a 'selective level meter'. I've had a google and can find lots of (mostly antique) models, but I can't seem to find anything that describes what one of these is. Am I right in guessing it's essentially a narrowband AM receiver with a power meter for the carrier? So a spectrum analyser with only one horizontal point? Are they typically more accurate than a spectrum analyser - or can I just use another analyser? Theo- I expect a frequency selective voltmeter will have an accuracy in the order of 5% (1/2 dB) or 10% (1 dB) of its full scale reading. The spectrum analyzer probably has an accuracy measured in dB, probably greater than 1 dB. I might depend on another analyzer if that was the only option. Then the question would be whether the second analyzer is less accurate than the one you're trying to calibrate! Somewhere along the line you need a standard to compare with. Fred K4DII |
#4
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Selective level meter
Fred McKenzie wrote:
I expect a frequency selective voltmeter will have an accuracy in the order of 5% (1/2 dB) or 10% (1 dB) of its full scale reading. The spectrum analyzer probably has an accuracy measured in dB, probably greater than 1 dB. Thanks, that's useful to know. Theo |
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