US 12,138,068 B2
Techniques for characterizing a nonlinearity of a time-to-digital converter in an optical measurement system
Sebastian Sorgenfrei, Playa Vista, CA (US); Viswanath Ambalapuzha Gopalakrishnan, Culver City, CA (US); Katherine Perdue, Los Angeles, CA (US); Isai Olvera, San Jose, CA (US); and Ryan Field, Culver City, CA (US)
Assigned to HI LLC, Culver City, CA (US)
Filed by HI LLC, Los Angeles, CA (US)
Filed on Mar. 16, 2021, as Appl. No. 17/202,588.
Claims priority of provisional application 63/059,382, filed on Jul. 31, 2020.
Claims priority of provisional application 62/992,502, filed on Mar. 20, 2020.
Prior Publication US 2021/0290146 A1, Sep. 23, 2021
Int. Cl. G04F 10/00 (2006.01); A61B 5/00 (2006.01); A61B 5/026 (2006.01); G01J 1/44 (2006.01); H03M 1/50 (2006.01)
CPC A61B 5/4064 (2013.01) [A61B 5/0261 (2013.01); A61B 5/7225 (2013.01); G04F 10/005 (2013.01); G01J 1/44 (2013.01); H03M 1/50 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An optical measurement system comprising:
a signal generator configured to generate a signal; and
a processing unit configured to
direct the signal generator to apply the signal to a time-to-digital converter (TDC) included in the optical measurement system, and
generate, based on timestamp symbols recorded by the TDC in response to the signal, characterization data representative of a nonlinearity of the TDC;
wherein the generating of the characterization data comprises:
generating a histogram of the timestamp symbols recorded by the TDC, the histogram including a plurality of time bins; and
determining a code density metric for each time bin of the histogram, the code density metric representative of a density of timestamp symbols at each time bin of the histogram, the determining the code density metric being performed in accordance with Code density[i]=hist_bin[i]/Σall binshist_bin[i]*Btotal, where Code density[i] is the code density metric, i is an index for each time bin of the histogram, hist_bin[i] represents a value in the histogram at each time bin i, Btotal represents a total number of time bins in the histogram, and Σall binshist_bin[i] represents a sum of all the values in the histogram.