Abstract:
Channel changing apparatus for automatically scanning or incrementing the channel on a radio, television or other receiver and pausing for a set period of time on each channel to allow a user to preview to content. A scan speed adjustment control allows the user to vary the length of the preview period. The channel changing apparatus may be provided on a remote control device or integral to the receiver.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to channel selection on a radio or television and in particular to a variable delay automatic channel scanning function. 
     2. Description of the Related Art 
     Televisions and AM/FM radios are known to have an automatic “scan” feature which allows the user to preview each available television channel or radio station for a predetermined period. After the period has elapsed, the television or radio receiver is incremented to the next channel in a list or to the next detected station having a sufficiently strong signal. When the user finds content of interest in the presently selected channel or station, the scanning operation may be halted by operating a control. 
     Usually, the period of time for which the receiver is delayed before incrementing the channel is fixed. Depending upon the length of the fixed period, the viewing or listening habits of a particular user, and the type of content, the fixed period may be inappropriate or inconvenient. If the period is too brief, the user may not have enough time to appreciate the content and stop the scanning. Likewise, if the period is too long, the scanning operation may become cumbersome. 
     U.S. Pat. No. 5,886,746 to Yuen et al. discloses a method for channel scanning in which it is possible for the user to program the period of time that a channel is displayed before another channel is displayed to either of two preset periods: five seconds or 15 seconds. 
     BRIEF SUMMARY OF THE INVENTION 
     A channel changing apparatus for a radio or television receiver comprising a receiver for receiving a plurality of channels is provided. The channel changing apparatus further comprises an automatic channel scan for causing the receiver to select a first one of the plurality of channels and to select a second one of the plurality of channels after a set scan period has elapsed, and a scan speed adjustment for selectively setting the scan period. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a schematic view of a channel changing apparatus in accordance with one embodiment of the invention; and 
     FIG. 2 is a plan view of a remote control device embodying the channel changing apparatus in accordance with one embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is a schematic representation of a channel changing apparatus  10  embodying a variable delay channel scan in accordance with one embodiment of the invention. The apparatus  10  comprises an automatic channel scanning circuit  14  which controls the changing of channels on a receiver  12 , such as a radio or television receiver. 
     When activated, the scanning circuit  14  causes the receiver  12  to scan, that is, increment or decrement, through a list of channels or frequencies at a specific interval or speed. The list can be selected by the user or include all detected stations having a sufficiently strong signal. This allows a user to preview each channel for the set time period, as determined by the interval, before the scanning circuit  14  causes the receiver  12  to increment or decrement to the next channel in the list. The scanning circuit  14  can scan in either a forward or a reverse direction. The speed can be increased or decreased within a given range. For example, the delay or pause time at each station can be selected within a range of 0.5 to 10 seconds. The delay can be set over a continuous range, such that it is continuously variable. As used herein, the term continuously variable refers to the ability to be set to any of an infinite number of values within a given range, or the substantial appearance of such. 
     The scanning circuit  14  is controlled by a channel scanning control  16  and a scanning speed control  18 . The scanning control  16  allows the user to selectively initiate and discontinue scanning in either the forward or reverse direction by the scanning circuit  14 . Once initiated, scanning continues in the selected direction until the user directs the scanning control  16  to discontinue the operation of the scanning circuit  14 . 
     The speed control  18  allows the user to control the speed at which the channel scanning circuit  14  scans through the channels of the receiver  12 . Selecting a higher speed decreases the set time period between incrementing or decrementing operations. Similarly, selecting a lower speed increases the period. The speed may be adjusted at any time, including during scanning, in order to speed up or slow down the scanning. 
     In FIG. 2, a remote control device  20  is shown which partially embodies the present invention. In this embodiment, the channel scanning control  16  comprises a forward scan button  22  and a reverse scan button  24 . In an initial or inactive state, pressing the forward scan button  22  causes the scanning circuit  14  to begin incrementing the channels of the receiver  12  in a forward direction, pausing for the set period on each channel. Pressing the forward scan button  22  again, or pressing the reverse scan button  24 , causes the scanning circuit  14  to discontinue scanning. Likewise, pressing the reverse scan button  24  from the inactive state causes the scanning circuit  14  to begin scanning in the reverse direction. This reverse scanning operation can also be stopped by pressing either scan button  22 ,  24 . It should be appreciated that other known control means can be substituted for the scan buttons  22 ,  24 , such as a toggle switch or a single button. 
     In the embodiment of FIG. 2, the scanning speed control  18  comprises a thumb wheel  26 . Rolling the thumbwheel  26  in a forward direction  28  selectively increases the scanning speed, thereby decreasing the set period, up to a maximum speed (or a minimum period). Rolling the thumbwheel  26  in a reverse direction  30  selectively decreases the scanning speed, thereby increasing the set period, down to a minimum speed (or up to a maximum period length). It should be appreciated that other known control means can be substituted for the thumb wheel  26 , such as a turn knob, a pair of increase and decrease buttons, a toggle switch, or a sliding selector. An additional alternative would be to provide a means for entering a numeric value for the period length using a keypad. 
     Further, while the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.