RF Lab VSA
COMP3054 LAB 6 Name: ID# Section: LAB 6: Frequency Domain Measurements Using the Vector Signal Analyzer
Objective: Measure: frequency and amplitude, channel power/ band power, relative frequency and amplitude, improving resolution, and spectrogram displays using the VSA
Section A: Measuring Frequency and Amplitude
1. recalling the demo named 50PCAM.htm in the: " File\Recall\Recall Demo\Help\Signals\AM FM PM" directory. When played back, the signal should look like this:
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The analyzer is set to analog demodulation mode, with amplitude demodulation selected. Traces are configured to show the pre-demodulation spectrum and time domain on the left, and the demodulation results in frequency and time domain on the right. The time length, number of analysis points, and resolution bandwidth have been changed from the default to make it easier to recognize the sinewave in the modulation. Note that the pre-demodulation time domain display is not baseband time (as you would see using an oscilloscope) but is instead IF time—the time domain signal you would see in the IF of a receiver. In this case, the receiver center frequency is very close to that of the carrier, causing a low-frequency change in the apparent amplitude of the signal.
The pre-demodulation spectrum shows the signal spectrum including the AM sidebands and distortion sidebands. The demodulation spectrum shows the spectrum of the modulating signal, including its distortion. The offset markers on pre-demodulation and demodulation result traces indicate the frequency of the modulating signal and the relative amplitude of the distortion in the modulating signal. The approximately 3 dB difference is due to the fact that the
Objective: Measure: frequency and amplitude, channel power/ band power, relative frequency and amplitude, improving resolution, and spectrogram displays using the VSA
Section A: Measuring Frequency and Amplitude
1. recalling the demo named 50PCAM.htm in the: " File\Recall\Recall Demo\Help\Signals\AM FM PM" directory. When played back, the signal should look like this:
_______________________________________________________________________________________________
The analyzer is set to analog demodulation mode, with amplitude demodulation selected. Traces are configured to show the pre-demodulation spectrum and time domain on the left, and the demodulation results in frequency and time domain on the right. The time length, number of analysis points, and resolution bandwidth have been changed from the default to make it easier to recognize the sinewave in the modulation. Note that the pre-demodulation time domain display is not baseband time (as you would see using an oscilloscope) but is instead IF time—the time domain signal you would see in the IF of a receiver. In this case, the receiver center frequency is very close to that of the carrier, causing a low-frequency change in the apparent amplitude of the signal.
The pre-demodulation spectrum shows the signal spectrum including the AM sidebands and distortion sidebands. The demodulation spectrum shows the spectrum of the modulating signal, including its distortion. The offset markers on pre-demodulation and demodulation result traces indicate the frequency of the modulating signal and the relative amplitude of the distortion in the modulating signal. The approximately 3 dB difference is due to the fact that the