Telecommunications – Receiver or analog modulated signal frequency converter – Signal selection based on frequency
Reexamination Certificate
1999-03-10
2002-05-14
Trost, William (Department: 2685)
Telecommunications
Receiver or analog modulated signal frequency converter
Signal selection based on frequency
C455S150100, C455S131000, C375S316000, C375S350000
Reexamination Certificate
active
06389270
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to circuits for station scan functionality in a radio receiver. More specifically, the present invention relates to techniques for conducting a station scan in a digital receiver.
2. Description of the Related Art
In a given geographic area, numerous stations may be broadcasting radio frequency (RF) signals on different channels. These RF signals may be AM or FM signals and may include desired program information. A radio receiver present within this geographic area, either fixed or mobile, will attempt to receive and recover the program information being broadcast by the stations. Often it is desirable for the radio receiver to have the ability to scan for the presence of stations in the geographic area. For example, when a person is traveling in an automobile through an unfamiliar geographic area, that person will likely not know the channels on which stations are broadcasting program information. Such station scan to capabilities, however, often require a radio receiver to include additional circuitry that may add undesirable costs and complexity to the radio receiver.
SUMMARY OF THE INVENTION
In accordance with the present invention, station scan circuitry efficiently determines the presence of a station on available channels. Channels are analyzed to determine if the signal power on a given channel exceeds a threshold value. A comparison is also made between the desired channel signal strength and the adjacent channel signal strength. If the signal power and the ratio of signal strengths exceed selected threshold levels, the station scan circuitry indicates that a station has been found. To make the signal strength ratio comparison, the station scan circuitry makes a comparison of the post-filter signal strength and the pre-filter signal strength for the received signal.
REFERENCES:
patent: 4123715 (1978-10-01), Fathauer
patent: 4135158 (1979-01-01), Parmet
patent: 4404430 (1983-09-01), Ogita
patent: 4461026 (1984-07-01), Priniski
patent: 4476581 (1984-10-01), Bragas
patent: 4646150 (1987-02-01), Robbins et al.
patent: 4688110 (1987-08-01), Fricke
patent: 4698670 (1987-10-01), Matty
patent: 4821097 (1989-04-01), Robbins
patent: 4823390 (1989-04-01), Wittrock
patent: 5339455 (1994-08-01), Vogt et al.
patent: 5430890 (1995-07-01), Vogt et al.
patent: 5548831 (1996-08-01), Bjiker et al.
patent: 5613230 (1997-03-01), Gottfried et al.
patent: 5740523 (1998-04-01), Nakajima et al.
patent: 5751806 (1998-05-01), Ryan
patent: 5909644 (1999-06-01), Tomiyama
patent: 6192089 (2001-02-01), Corleto et al.
Chan Brian P. Lum Shue
Nohrden James M.
Cirrus Logic Inc.
Lin, Esq. Steven
Tran Congvan
Trost William
LandOfFree
Station scan method and apparatus for radio receivers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Station scan method and apparatus for radio receivers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Station scan method and apparatus for radio receivers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2858653