Random hardware fault and degradation protection apparatus for time-of-flight receiver

A time-of-flight light detection system includes: a plurality of circuits arranged sequentially along a signal path that comprises a plurality of signal channels, the plurality of circuits including a first circuit and a second circuit arranged downstream from the first circuit; a reference signal source configured to generate a plurality of reference signals, where each of the plurality of signal channels at the first circuit receives at least one of the plurality of reference signals; and an evaluation circuit coupled to the plurality of signal channels to receive a processed reference signal from the signal path, the evaluation circuit further configured to compare the processed reference signal to a first expected result to generate a first comparison result.