NF FRA51602, Инструкция по эксплуатации

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1.3 Operating principles
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FRA 51602
1.3 Operating principles
1.3.1 Basic principles
This instrument measures the frequency transfer characteristics of the equipment under test (EUT) with
high accuracy over a wide dynamic range. It is equipped with a sweep oscillator and two analysis input
channels (CH1,CH2), and makes highly-accurate calculations of analysis frequency component vectors
(amplitude and phase) from Fourier coefficients obtained from a discrete Fourier transform of the input
signals. By measuring the EUT input signal (Vin) and output signal (Vout) with the analysis input channels
(CH1 and CH2) and calculating the vector ratio (CH1/CH2), the gain and phase at the analysis frequency
(f) of the EUT can be obtained.
Figure 1-4 Principal of frequency transfer characteristic measurement with the FRA 51602
The loop characteristic measurement and impedance characteristic measurement both differ from the
frequency response measurement only in the connections and the units of the measurement results, so the
measurement principle is the same as for the frequency response measurement described above.
One round of measurement produces the gain and phase values at the analysis frequency (f). By measuring
the gain and phase while sweeping the oscillator and analysis frequencies, frequency characteristics such as
Bode plots can be obtained. Also, when auto-range is set, the range of the analysis module is optimized for
each frequency being measured, so the dynamic range is greatly increased for measurement of A/D
converters.
～
A/D A/D
OSC CH1 CH2
EUT
DFT DFT
Frequency
= f
V2(f) V1(f)
|Gain(f)| = |V1(f)|
÷
|V2(f)|
Phase(f) =
∠
V1(f)
－ ∠
V2(f)
Vin Vout
FRA51602