| 摘要 |
"Radio Pager Tone Alarm Circuit For Generating Variable Duty Constant Audio Frequency Pulses Modulated With Unique Tone Pattern" In a radio pager, a paging signal containing the pager's own identifier and a particular alert tone pattern is received. On receiving this signal, constant audio-frequency pulses having a duty ratio increasing as a function of time are generated and modulated with the alert tone pattern. The modulated pulses are applied to a loudspeaker for alerting the user with an escalating alert sound.
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