ITSPECTRALANALYSIS

Enable and configure spectral analysis on receiver

Platform:

OEM719, OEM729, OEM7500, OEM7600, OEM7700, OEM7720, PwrPak7, CPT7, CPT7700, SMART7

Use this command to view the spectrum in a range of frequencies. The ITSPECTRALANALYSIS command enables and configures the spectral analysis. The spectrum is viewed by plotting the PSD samples in the ITPSDFINAL log.

Decreasing the update period or increasing the FFT size will impact receiver idle time. The idle time should be monitored to prevent adverse effects on receiver performance.

Due to the high volume of data, a higher bandwidth medium, such as USB or Ethernet, is recommended when monitoring signals using the Interference Toolkit.

To enable and configure spectral analysis on the secondary antenna of dual antenna receivers (OEM7720, PwrPak7D, PwrPak7D-E1, PwrPak7D-E2 and CPT7), use the ITSPECTRALANALYSIS_1 command.

Message ID: 1967

Abbreviated ASCII Syntax:

ITSPECTRALANALYSIS mode [frequency] [updateperiod] [FFTsize] [timeavg] [integration_window]

Factory Default:

ITSPECTRALANALYSIS off

ASCII Example:

ITSPECTRALANALYSIS predecimation gpsl1 500 1K 20 1

Field

Field Type

ASCII Value

Binary Value

Description

Format

Binary Bytes

Binary Offset

1

ITSPECTRAL
ANALYSIS header

-

-

Command header. See Messages for more information.

-

H

0

2

mode

See Table: Data Sources for PSD Samples

Set the view mode.

Enum

4

H

3

frequency

See Table: Frequency Types

Set the frequency band to view.

Enum

4

H+4

4

updateperiod

50 to 100000

The spectrum update rate in milliseconds.

The update period is limited by the FFT size chosen. For 32k the minimum update period is 100 ms and for 64k the minimum update period is 200 ms.

(default = 1000)

Ulong

4

H+8

5

FFTsize

See Table: FFT Sizes

The frequency resolution of the spectrum.

(default = 1k)

Enum

4

H+12

6

timeavg

0 to 50

Time averaging window in seconds. 0 means no time averaging.

(default = 10)

Ulong

4

H+16

7

integration window

1 to 1024

The integration window size of FFT samples. 1 means no integration.

(default = 5)

Ulong

4

H+20

Data Sources for PSD Samples

Binary Value

ASCII Value

Description

0

OFF

Disable spectral analysis

1

PREDECIMATION

Perform spectrum analysis on the pre-decimated spectrum.

This can be used to see a wide view of the spectrum for an RF path (L1, L2 or L5).

2

POSTDECIMATION

Perform spectrum analysis on the post-decimated spectrum.

This is narrower than predecimation and is used to see the spectrum for a given signal.

3

POSTFILTER

Perform spectrum analysis on the post-filtered spectrum.

This can be used when either bandpass or notch filters have been enabled to see the spectrum after the filters are applied.

The post-filter spectrum is not available for the Galileo AltBOC frequency. Only the pre-decimation and post-decimation spectrums are available for Galileo AltBOC.

Frequency Types

Binary Value

ASCII Value

Description

0

GPSL1

GPS L1 frequency

1

GPSL2

GPS L2 frequency

2

GLONASSL1

GLONASS L1 frequency

3

GLONASSL2

GLONASS L2 frequency

4

Reserved

5

GPSL5

GPS L5 frequency

61

LBAND

Inmarsat L-Band frequency

7

GALILEOE1

Galileo E1 frequency

8

GALILEOE5A

Galileo E5A frequency

9

GALILEOE5B

Galileo E5B frequency

10

GALILEOALTBOC

Galileo AltBOC frequency

11

BEIDOUB1

BeiDou B1 frequency

12

BEIDOUB2

BeiDou B2I frequency

13

QZSSL1

QZSS L1 frequency

14

QZSSL2

QZSS L2 frequency

15

QZSSL5

QZSS L5 frequency

16

QZSSL6

QZSS L6 frequency

17

GALILEOE6

Galileo E6 frequency

18

BEIDOUB3

BeiDou B3 frequency

19

GLONASSL3

GLONASS L3 frequency

20

NAVICL5

NavIC L5 frequency

21

BEIDOUB1C

BeiDou B1C frequency

22

BEIDOUB2A

BeiDou B2a frequency

23

BEIDOUB2B

BeiDou B2b frequency

FFT Sizes

Binary Value

ASCII Value

Description

0

1K

1K FFT, 1024 samples

1

2K

2K FFT, 2048 samples

2

4K

4K FFT, 4096 samples

3

8K

8K FFT, 8192 samples

4

16K

16K FFT, 16384 samples

5

32K

32K FFT, 32768 samples

6

64K

64K FFT, 65536 samples

The 64k FFT is not available in post-decimation or post-filter modes.