Agilent Technologies 89410A User Manual

Why Use Analog Demodulation Mode?
The best way to make many measurements often includes the ability to
characterize the amplitude, frequency, and phase relationships between signal
components. Analog Demodulation mode provides this capability. For additional
details on this mode see “Analog Demodulation Concepts” later in this book.
Analog demodulation is derived from Vector Mode. The previous block diagram
indicates where analog demodulated measurements branch off from vector
measurements in the measurement process. Analog demodulation alters the time
record so that all operations past this point operate on demodulated data.
AM, FM, and PM signals commonly consist of a high frequency carrier signal
modulated by a lower frequency audio, video, or data signal. For these signals,
analog demodulation removes the carrier frequency leaving the modulating signal
which is contained in the sidebands of the carrier signal. An example of this
application is included in “Demodulating an Analog Signal” earlier in this book.
The most obvious use for analog demodulation is in analyzing intentionally
modulated signals as noted above. However, analog demodulation is also useful in
analyzing signals which are not intentionally modulated. For example the user may
choose to:
l Apply phase and frequency demodulation to oscillator or synthesizer designs
to examine phase and frequency trajectories during frequency hops or to
establish phase lock loop lock-up time. For an example of this type of
application see the “Characterizing a Transient Signal” chapter, earlier in this
book.
l Demodulate a burst signal to evaluate wait time in order to determine when a
signal stabilizes.
l Amplitude and phase demodulate sidebands to determine the type of
modulation present in phase noise. An example of this application is shown in
the “Measuring Phase Noise” chapter, earlier in this book.
l Demodulate bearing noise in mechanical measurements to examine
frequency instability.
Choosing an Instrument Mode
17 - 6

Agilent Technologies 89410A Specifications

General

Brand	Agilent Technologies
Model	89410A
Category	Measuring Instruments
Language	English