FM Receiver for general programs and special announcements
Patent 4435843 Issued on March 6, 1984. Estimated Expiration Date: 
November 9, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 9, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3922607 Frequency identification circuit for broadcast traffic information reception systems Traffic information radio signal receiver Patent #: 4334320 InventorsAssigneeApplicationNo. 06/319654 filed on 11/09/1981US Classes:455/205, Frequency or phase modulation340/825.72, Wireless link340/825.73, Plural frequencies455/228, Responsive to specified modulation (e.g., call alarm, Conelrad)455/45, Via subcarrier455/701Tone coded squelchExaminersPrimary: Ng, Jin F.Attorney, Agent or FirmInternational ClassG08G 1/09 (20060101)Foreign Application Priority Data1981-05-27 DEAbstractTo improve reliability of recognition of an announcement recognition (AR) signal radiated by a transmitter upon broadcasting an announcement (e.g. traffic information, news, etc.), in the form of AM modulation of a 57 kHz auxiliary subcarrier, in which the subcarrier may also be modulated by other control signals, the subcarrier is filtered in the receiver, demodulated, and the degree of all modulations, regardless of frequency, on the subcarrier is sensed, and if the modulation changes significantly, for example rises from 60% modulation to 90% modulation (50% change), a switch (4) is activated which inhibits transmission of audio programs from an external source, such as a tape recorder (5), tuner tuned to another station, or the like, and reproduces the announcement being broadcast; termination of the AR signal, forming the AR modulation on the subcarrier, causes the switch to revert for reproduction of previously controlled audio information.Other References
| |
