Analyze: File formats

△ Index ▷ Usage ▷ Examples ▷ Parameters ▷ Calibration ▼ File format ▷ How it works
▾ FFT data ▾ Reference spectrum ▾ Reference signal ▾ Gain correction ▾ Matrix correction ▾ Window function ▾ Raw samples

All files are ASCII, with tab separated, numeric columns. There is a header line starting with a #. This line is ignored on read.
Applications like Gnuplot can process this files directly as well as LibreOffice and even Excel can read them out of the box (simply rename to *.xls).

FFT data – data.dat

Column Symbol Description
$1 f Frequency
$2 |U| Amplitude of U(f) or nominator respectively
$3 arg U Phase angle of U(f) or nominator respectively in degrees
$4 |I| Amplitude of I(f) or denominator respectively
$5 arg I Phase angle of I(f) or denominator respectively in degrees
$6 |Z| Amplitude of the impedance U(f)/I(f) or transfer function
$7 arg Z Phase angle of the impedance U(f)/I(f) or transfer function in degrees
$8 re Z Real part of the impedance U(f)/I(f) or transfer function
$9 im Z Imaginary part of the impedance U(f)/I(f) or transfer function
$10 weight Relative weight
$11 delay Group delay d(U/I)/dω
$12 channel Channel 0 for first (or the only) channel, 1 for the second channel in stereo mode
optional for each enabled harmonic ...
$13 |Z2| Amplitude of the 2nd harmonic
$14 arg Z2 Phase of the 2nd harmonic in degrees
$15 re Z2 Real part of the 2nd harmonic
$16 im Z2 Imaginary part of the 2nd harmonic

From the above columns you may calculate the following parameters for one-port measurements. Rref is the reference resistor used.

Symbol Description Formula Unit Remarks
ESR equivalent series resistor $8 · Rref Ω
ESC equivalent series capacitor
-1 2 π · $9 · R ref F only if $9 < 0
ESL equivalent series inductor
$9 · R ref 2 π · $1 H only if $9 > 0
|Z| absolute value of the impedance $6 · Rref Ω
tan δ dissipation factor
$8 / |$9|

Reference signal (frequency domain) – spectrum.dat

Column Symbol Description
$1 f Frequency
$2 |Ref| Amplitude of Ref(f)
$3 arg Ref Phase angle of Ref(f)
$4 re Ref Real part of Ref(f)
$5 im Ref Imaginary part of Ref(f)
$6 harmonic Ordinal of the harmonic. Negative values indicate the second channel in case two channel mode is activated.

Reference signal (time domain) – ref.dat

Column Symbol Description
- line number
Sample index n
$1 ref(n) Sample value in range [-1..1]

Gain correction file – gain.dat

Column Symbol Description
$1
f Frequency
$2 re Real part of gain difference
$3 im Imaginary part of gain difference
$4 abs Absolute value of gain difference
$5 arg Phase angle of gain difference in degrees

On input (option gr) only the first three columns are used.

Matrix correction file – matrix.dat

Column Symbol Description
$1
f Frequency
$2 re cll Real part of coefficient cll
$3 im cll Imaginary part of coefficient cll
$4 re clr Real part of coefficient clr
$5 im clr Imaginary part of coefficient clr
$6 re crl Real part of coefficient crl
$7 im crl Imaginary part of coefficient crl
$8 re crr Real part of coefficient crr
$9 im crr Imaginary part of coefficient crr
$10 |cll| Absolute value of coefficient cll
$11 arg cll Phase angle of coefficient cll in degrees
$12 |clr| Absolute value of coefficient clr
$13 arg clr Phase angle of coefficient clr in degrees
$14 |crl| Absolute value of coefficient crl
$15 arg crl Phase angle of coefficient crl in degrees
$16 |crr| Absolute value of coefficient crr
$17 arg crr Phase angle of coefficient crr in degrees
$18 |L∞| Amplitude of the 1st channel during calibration with Z = ∞
$19
arg L
Phase of the 1st channel during calibration with Z = ∞ in degrees
$20
|R|
Amplitude of the 2nd channel during calibration with Z = ∞
$21
arg R
Phase of the 2nd channel during calibration with Z = ∞ in degrees
$22
|L0|
Amplitude of the 1st channel during calibration with Z = 0
$23
arg L0
Phase of the 1st channel during calibration with Z = 0 in degrees
$24
|R0|
Amplitude of the 2nd channel during calibration with Z = 0
$25
arg R0
Phase of the 2nd channel during calibration with Z = 0 in degrees
only for 3 point calibration ...
$26 |L1| Amplitude of the 1st channel during calibration with Z = 1
$27
arg L1
Phase of the 1st channel during calibration with Z = 1 in degrees
$28
|R1|
Amplitude of the 2nd channel during calibration with Z = 1
$29
arg R1
Phase of the 2nd channel during calibration with Z = 1 in degrees

The file contains an array of complex 2×2 matrices [ c ll c lr c rl c rr ] . On input (option zr) only the first 9 columns are used. → matrix calibration

The physical meaning of the coefficients is:

Coefficient Meaning
cll Channel 1 gain
clr Cross talk from channel 2 to channel 1
crl Cross talk from channel 1 to channel 2
crr Channel 2 gain

window.dat - window function

Column Symbol Description
- line number
sample index n
$1 win(n) Relative value of the window function at index n

raw.dat - raw data

Column Symbol Description
- line number
sample index n
$1 L(n) Channel 1 sample value in range [-1..1)
$2 R(n) Channel 2 sample value in range [-1..1)