초록 ▼

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 stor

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.

대표청구항 ▼

A method for trimming the frequency of a piezoelectric crystal oscillator in a timepiece having a count-down circuit coupled to the oscillator to receive an input signal therefrom and provide a lower frequency output signal, time indicating means coupled to the count-down circuit to be activated the

A method for trimming the frequency of a piezoelectric crystal oscillator in a timepiece having a count-down circuit coupled to the oscillator to receive an input signal therefrom and provide a lower frequency output signal, time indicating means coupled to the count-down circuit to be activated thereby, the piezoelectric crystal oscillator having a nominal frequency above a desired frequency, and an inhibit circuit means to periodically start blocking of oscillator pulses and preset a counter to a first count number stored in a nonvolatile memory circuit, said counter being responsive to the output of the oscillator for increasing the count preset therein to a second predetermined count, said inhibit circuit means stopping the blocking of oscillator pulses in response to the second predetermined count of said counter, wherein said first count number is determined and written into said nonvolatile memory circuit, including the steps of: detecting signals externally indicating untrimmed oscillator frequency generated by the untrimmed oscillator; determining the first count number such that the difference count between the first and second count equals the frequency difference between the untrimmed oscillator and the desired frequency; permanently writing the first count into said memory circuit.