Avalanche Diode Counter Testing via Reference Pulse

The patent applies preliminary action by introducing a reference circuit that generates a reference pulse signal before actual photoelectric conversion testing. This reference signal allows the counter to be pre-tested and calibrated, ensuring the counting mechanism works correctly before measuring photon-induced signals. The reference circuit operates independently of incident light, providing a known test input to verify the entire signal chain from pulse generation through counting.

The patent uses an intermediary approach by introducing a reference pulse signal as a mediator between the test input and the counter. This reference signal acts as a control variable that allows indirect verification of the counter's functionality. By comparing the counted reference pulses against an expectation value, the system can verify counter operation without directly observing the photoelectric conversion process itself.

The patent applies universality by designing the counter to serve multiple functions: it counts both light-dependent pulse signals from the photoelectric conversion unit and light-independent reference pulse signals from the reference circuit. This multi-functionality allows the same counter hardware to be used for both operational photon counting and self-verification testing, eliminating the need for separate testing equipment and reducing overall system complexity.

The patent implements self-service by enabling the photoelectric conversion apparatus to test its own counter functionality using its existing components. The reference circuit generates test signals that pass through the same signal path and are counted by the same counter used for photon detection. This self-testing capability allows the apparatus to verify its own operational status without external testing equipment, reducing complexity while maintaining verification capability.