Abstract:
This system is for automatically controlling a radio receiver to provide an audible broadcast of the weather alert from weather stations. It may also be incorporated in a multi-band radio for automatically switching between AM/FM broadcast and weather alert broadcast. A scanning means operates continuously to tune the weather band portion of the receiver automatically in a stepping manner to receive signals from the weather stations regardless of whether the receiver is operating in any selected AM or FM broadcasting in the multi-band radio. A combination switching comparator and switching means automatically switch the system over to the weather broadcast when a weather alert signal is detected. The switching means also automatically switches the system back to the original selected broadcast after the termination of the weather alert broadcast.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an automatic control system for receiving a weather alert broadcast, and more particularly a radio system which operates automatically for receiving and broadcasting a weather alert from weather stations. 
     Weather alerts are broadcasted by weather stations in various regions covering different parts of the country and the world. Weather radios are receivers for listening to such weather alert broadcasts in weather bands operated in the frequency modulated (FM) signal. Heretofore, weather alerts radio receivers operate to receive first a weather alert alarm signal, and after hearing the alarm signal, it is necessary for the user to switch the receiver manually to the broadcasting mode of the weather station in order to listen to the actual weather alert broadcast. Such systems are, for example, shown in U.S. Pat. No. 4,633,515 to Uber et al, and U.S. Pat. No. 4,392,248 to Eckels et al. Since the weather radio user may not be located immediately near to the receiver to switch it over to the broadcasting mode, or that the user may be preoccupied with other tasks and is unable to operate the change over switch, the operation of such system is therefore awkward and inconvenient to carry out. Furthermore, it is necessary for the listener to change the tuning of the receiver manually to a different channel so as to receive a broadcast from each different weather station. 
     A weather band may be incorporated in a multi-band radio receiver which may be operated to receive broadcasts from any of the AM, FM, or weather band selectively. However, the drawback in such multi-band radio receiver is that each broadcast band operates independently such that the weather alert alarm signal can not be received when the radio is operating in either the AM or FM band. The radio must be set at the weather band at all times in order to receive the weather alert alarm signal. The ambient noise in such weather broadcast band is quite high during the absence of any weather alert alarm such that it is annoying to the user. For this reason, users tend to turn off the weather band entirely, resulting in the danger of not receiving any weather alert alarm signal. 
     SUMMARY OF THE INVENTION 
     It is a principal object of the present invention to provide a control system which operates automatically for controlling the weather band radio for receiving and broadcasting the weather alert announcement. 
     It is another object of the present invention to provide a weather alert radio receiver having selective automatic mode and manual mode which operate to receive and to broadcast a weather alert announcement from various weather stations. 
     It is yet another object of the present invention to provide a control system for a multi-band AM/FM and weather band radio receiver which operates automatically for receiving and broadcasting weather alert announcements regardless of any selected band it is normally operating, and it will also automatically return to the originally selected AM or FM band at the termination of the weather alert broadcast. 
     The multi-band radio receiver of the present invention includes AM and FM bands for receiving AM and FM broadcasts and a weather band for receiving weather warning alert and weather broadcast from a plurality of weather stations to provide automatically an audible output of the weather warning alert and the weather broadcast regardless of whether or not the receiver is normally operating in the AM or FM band or the weather band. The broadcasts are announced by an audio means of the receiver. The receiver includes an automatic control comprises a frequency stepping circuit means operative continuously for scanning and tuning the receiver to search the plurality of weather stations for the weather alert and weather broadcast transmitted by a carrier frequency signal. A detecting means is adapted to segregate the weather warning alert and weather broadcast from the carrier frequency signal. A squelch circuit means is connected to the detecting means and in combination therewith adapted to determine the presence of the weather warning alert and the weather broadcast. A filter means is connected to the detecting means and is adapted to provide a trigger output signal in response to the weather warning alert. An alert audio oscillator means is connected to the filter means and is adapted to generate a unique alert signal when a weather warning alert is received. A switching comparator means coupled to the detecting means and is adapted to provide an actuation output signal when the weather warning alert and weather broadcast are present. A switching means is connected to the switching comparator means and the alert audio oscillator means and is operative by the actuation output signal for conveying the unique alert signal and weather broadcast to the audio means. An auto lock circuit means is coupled to the frequency stepping circuit means and the detecting means and is operative to lock the frequency stepping circuit means at one of the plurality of weather stations which is presently announcing the weather warning alert and the weather broadcast. An AM/FM output switch means is connected to the squelch circuit means and is adapted to disconnect the AM or FM broadcast from the audio means while the unique alert signal and weather broadcast is being announced by the audio means, and it will re-connect the selected AM or FM broadcast to the audio means at the termination of the announcement of the unique alert signal and the weather broadcast. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of an automatic multi-band AM/FM and weather alert broadcasting radio receiver having a control system according to the present invention. 
     FIG. 2 is a schematic circuit diagram showing an exemplary embodiment of the radio receiver operative for carrying out the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the drawings wherein like reference numerals designate corresponding parts, as best shown in FIG. 1, weather alerts are broadcasted by various weather stations in a number of regions covering different parts of the country to indicate potential and current adverse weather conditions. Weather alerts are broadcasted in the frequency modulated FM signal by the weather stations. Such broadcast in a frequency modulated FM signal in high frequency is received through the antenna  10 , it is amplified initially by a radio frequency amplifier, WB RF amplifier  11 . The amplified signal is applied to a mixer  12  in which it is mixed with the oscillation signal generated by an oscillator  13  which is tuned to the broadcasting frequency of the weather station. An output signal having a frequency combination including an intermediate frequency of 455 KHz is produced by a mixer  12 . This output signal is then amplified by an intermediate amplifier  14  to a large amplitude FM signal containing the carrier radio frequency as well as the actual audio weather alert warning signal and weather broadcast. The amplified FM signal is then processed by a detector  15  to retrieve the weather alert signal and the weather broadcast from the carrier frequency. If the output of the detector  15  is connected directly to an audio amplifier  16  through the contact  17   a  of a selection switch  17 , the weather broadcast without the alert warning would be announced by the speaker  18 . The volume of the audio level may be selected by a volume control  19  provided between the detector  15  and the audio amp  16 . However, the above common weather band receiver requires the receiver to be activated at all time in order to listen to the weather alert and weather broadcast. Since the ambient noise of the weather bands is quite high when there is no weather broadcast, listeners tend to turn off the receiver, resulting in not hearing the adverse weather broadcast. The present invention provides an automatic control having an auto scan synchronizing circuit  20  which operates continuously to tune the oscillator  13  in a step manner through all the broadcasting frequencies of the weather stations. A filter  21  and a squelch circuit  22  are coupled to the detector  15 . The filter  21  segregates the alert warning signal such that when there is an alert warning signal broadcasted by any weather station, the output of the filter  21  will be high. The squelch circuit  22  detects the presence of the weather broadcast signal such that its output would be high when there is a weather alert broadcast. Both outputs of the squelch circuit  22  and filter  21  are applied to a switching comparator  23  which will turn on an audio oscillator  24  which generates a unique audio tone for warning the listener of the presence of a weather alert warning signal. When both inputs of the switching comparator  23  are high, namely, there is a weather alert warning signal as well as a weather broadcast, the switching comparator  23  will activate an electronic switching circuit  25  to first direct the unique audio tone signal to the audio amp  16  to provide an audible output by the speaker  18  followed by connecting the output from the detector  15  to the audio amp  16  to announce the weather broadcast. An auto lock circuit  26  is coupled between the squelch circuit  22  and the auto scan synchronizing circuit  20 . When a weather broadcast is detected by the squelch circuit  22 , the auto lock circuit  36  would temporarily lock the stepping operation of the auto scan synchronizing circuit  20  at the weather station presently announcing a weather alert broadcast. At the termination of the weather broadcast, when the squelch circuit  22  no longer detects a weather broadcast, it will de-activate the auto lock circuit  26  to return the tuning auto scan synchronizing circuit  20  again to the scanning operation for tuning the weather band receiver to the various weather stations to search for any weather alert signal and weather broadcast. 
     An AM and FM receiver may be incorporated in the present weather band receiver to provide a multi-band receiver. The FM broadcast is received through the antenna  10 , and, in a conventional manner the signal is mixed in a mixer  27  with the tuning frequency generated by an FM oscillator  28  so as to select an FM station and to produce an output consisting of the frequency combinations including the intermediate frequency of 455 KHZ. The intermediate frequency is processed in an IF circuit  29  which discriminates other frequencies except the intermediate frequency and selectively amplifies this high frequency signal. The audio FM signal is obtained in an AM/FM detector  30  by stripping off the carrier radio frequency. The audio FM signal is passed through an AM/FM output switch circuit  31  which normally connected the audio signal through the contact  17   b  of the selection switch  17  and volume control  19  to the audio amplifier  16  and finally to the speaker  18  to provide the audible output of the selected FM broadcast. Similarly, an AM broadcast is received through the AM antenna  32 . The AM signal is tuned and amplified by the AM portion of the IF circuit  29  which serves as the AM radio frequency tuning and intermediate frequency amplification. The AM signal is detected and segregated by the detector  30  and it is connected to the audio amplifier  16  through an AM/FM output switch circuit  31 , the contact  17   b  of selection switch  17  and volume control  19 , and subsequently to the speaker  18  to provide the audible output of the selected AM broadcast. The AM/FM output switch circuit  31  normally connects the audio signal to the audio amplifier  16  to the speaker  18 . However, it will be de-activated by the squelch circuit  22  when the squelch circuit  22  detects a weather broadcast, so that during the announcement of the weather broadcast, the AM and FM receivers are disconnected from the audio amplifier  16  and the speaker  18 . Accordingly, the multi-band combination radio receiver of the present invention, allows the receiver to be operated normally for listening to the AM or FM broadcast and yet when a weather alert signal and weather broadcast are detected, the receiver would automatically disconnect the AM or FM broadcast from the audio amplifier  16  and would connect the weather receiver portion to the audio amplifier  16  instead. At the termination of the weather broadcast, the electronic switching circuit  25  will disconnect the weather receiver portion from the audio amplifier  16  while the AM/FM output switch circuit  31  will re-connect the AM or FM broadcast signal to the audio amplifier  16  and to the speaker  18  to resume listening to the originally selected AM or FM broadcast. In the above manner, the listener would not miss listening to any weather alert broadcast from any weather station. This is particularly important for a traveller in a vehicle moving from a region covering by one weather station into another region covering by another weather station broadcasting an adverse weather alert. 
     As shown in the exemplary embodiment of the schematic circuit diagram FIG. 2, any signal from a weather station is received by the antenna  10  and it will be amplified by the RF amplifier including the transistor Q 1 , the signal is outputted to the mixer having transistor Q 2 . A detector and squelch integrated circuit U 3  provides the IF and detect functions for the signal. While the squelch integrated circuit U 3  in combination with diodes D 9  and D 8  determines the existence of the weather alert alarm in the signal. In the existence of a weather alert alarm signal, the output of the squelch integrated circuit U 3  will turn on the transistor Q 14  to activate the CPU U 4  so as to lock the auto scan synchronizing circuit IC 2  at the particular weather station having a weather alert broadcast as well as turning on transistors Q 7  and Q 8  to connect the weather band to the audio amplifier U 1  in order that the weather alert broadcast will be outputted to the audio amplifier U 1  for announcing by the speaker  18 . In absence of the weather alert alarm signal, the auto scan synchronizing circuit IC 2  in combination with the oscillator operates continuously for tuning the receiver in a stepping fashion through various predetermined carrier frequencies of the weather stations to seek for any weather alert and weather broadcast. 
     In the multi-band radio embodiment shown in FIG. 2, AM and FM receiver portions are also incorporated into the circuit. Normally, the system is set at a selected broadcast in either the AM or the FM band, and transistors Q 7  and Q 8  are turned on to connect the selected AM or FM broadcast to the audio amplifier control U 1  to operate the speaker  18 . In the meantime, the weather band portion of the radio operates continuously as described above while the selected AM or FM receiver portion is in operation. As soon as a weather alert alarm signal is detected by the squelch integrated circuit U 3 , it will also activate the AM/FM output switch circuit to disconnect the AM or FM broadcast to the audio amplifier so that only the weather band portion is connected to the audio amplifier to provide the audio output of the weather alert announcement. At the termination of the weather alert announcement, the squelch integrated circuit U 3  will cause the auto synchronizing circuit IC 2  to resume its stepping tuning operation through the weather stations and simultaneously will also activate the AM/FM output switch circuit to re-connect the previously selected AM or FM to the audio amplifier so as to resume the original AM or FM broadcast. 
     It will be appreciated by those skilled in the art that a manually operated multi-selection tuning switch may be used to replace the auto scan synchronizing circuit  20 . The tuning switch is connected to the CPU U 4  and adapted to tune the weather band portion to the predetermined weather stations, one at a time in a stepping manner, each time the tuning switch is operated. Also, other television receiver bands may be incorporated into the present multi-band radio receiver similar to the AM and FM band as described above. 
     While the present invention has been described in detail with regard to the preferred embodiment, it is appreciated that other variations of the present invention may be devised which do no depart from the inventive concept of the present invention.