US 12,143,116 B2
Time to digital converter calibration
Henrik Pia Sjöland, Lund (SE); Mohammed Abdulaziz, Lund (SE); and Tony Påhlsson, Lund (SE)
Assigned to TELEFONAKTIEBOLAGET LM ERICSSON (PUBL), Stockholm (SE)
Appl. No. 17/921,698
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed Apr. 28, 2020, PCT No. PCT/EP2020/061771
§ 371(c)(1), (2) Date Oct. 27, 2022,
PCT Pub. No. WO2021/219205, PCT Pub. Date Nov. 4, 2021.
Prior Publication US 2023/0170915 A1, Jun. 1, 2023
Int. Cl. H03M 1/10 (2006.01); G04F 10/00 (2006.01)
CPC H03M 1/1028 (2013.01) [G04F 10/005 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A method performed in a calibration unit for calibrating a Time to Digital Converter (TDC), wherein the TDC is configured to receive a signal with a reference frequency (FREF) and a signal from a Digital Controlled Oscillator (DCO), the method comprising:
receiving output data samples from the TDC for a predefined period of time;
performing a de-wrapping process on the data samples;
generating reference line segments from the data samples using a numerical fitting method;
calculating an error value for each of the output data samples associated to a TDC output level by calculating a deviation of each output data sample from a corresponding reference level of at least one reference line segment;
accumulating the error values of the data samples associated to a TDC output level in an accumulator of this TDC output level;
increasing a counter value of a TDC output level by one when an error value of a data sample associated with this TDC output level is added to its accumulator;
averaging the error values for each TDC output level by dividing the accumulated error value for each TDC output level in its accumulator by its counter value; and
generating a calibration lookup table comprising an error vector of the averaged error values for the TDC output levels.