tinySA | Main / USB command: correction

Correction table

There are two user controllable level correction mechanisms in the tinySA:

First is the leveloffset which is frequency independent and set by either doing a level calibration or using the ACTUAL POWER menu.

The second mechanism is the frequency dependent correction table. There re two tables, one for the low input and one for the high input. Each table has 10 entries for frequency dependent level corrections. The default table for the V0.3 HW low input contains these values

slot	frequency	value
0	10000	6.0
1	100000	2.8
2	200000	1.6
3	500000	-0.4
4	30000000	0.0
5	140000000	-0.4
6	200000000	0.4
7	300000000	3.0
8	330000000	4.0
9	350000000	8.1

The current content of the table is shown by entering correction low without any arguments. The data in the table can be modified by specifying the slot number and the new values.

Example: correction low 5 10000000 -0.5

This command will set slot 5 to 10MHz and a correction of -0.5dB. The frequencies specified in the table must be sorted in increasing frequency. Make sure you do a saveconfig after updating to save the new values to flash memory so they will survive reset.

There MUST be one entry in the low table for 30MHz and the correction for that frequency MUST be zero. You are free to choose which entry as long as the table is sorted in increasing frequency

Use of the correction table

All level measurements will use the frequency of the measurement to find the applicable correction.

Any frequency below the frequency in slot 0 will use the correction from slot 0
Any frequency above the frequency in slot 9 will use the correction from slot 9
Any in between frequency will use a frequency based linear interpolation to calculate the applicable correction

The correction table for the high input has frequency values set but all corrections are set to zero.