Apparatus is disclosed which is employed to provide an audible sound at a given repetition rate to enable one to test and calibrate a timing mechanism such as a watch which employs a non-audible frequency source, such as a crystal or quartz oscillator. The apparatus employs a pickup antenna and tuned circuit means which are responsive to the frequency radiated by the oscillator employed in the horological device to be tested. This frequency is processed by means of suitable circuitry to provide an output frequency within the audible range and of a repetition rate consistent with the repetition rate of a prior art mechanical horological device. The output frequency signal is applied to an audio transducer to thus provide an audible signal which is synchronized to the crystal oscillator signal to thereby enable a user to employ a prior art calibration instrument for testing and calibration of the above noted devices.
A method and apparatus for adjusting the frequency of piezoelectric crystal oscillator. The effective frequency of the oscillator is adjusted (trimmed) by periodically inhibiting pulses to the divider stage. The pulse inhibit circuit includes a nonvolatile programmable read-only-memory (ROM) to store binary complement information corresponding to the number of oscillator pulses to be suppressed. A counter is periodically preset with the binary complement information and the count advances in response to oscillator pulses. The difference count between the complement number and the counter's maximum count controls the number of pulses periodically suppressed. During manufacture/assembly of the timepiece, the ROM is programmed to contain the desired complement information.
