Abstract: Apparatus and methods are disclosed for broadcasting auxiliary data in an FM stereo broadcasting system. The auxiliary data is broadcast in addition to regular audio broadcast programs including musical selections, and includes data which identifies the musical selections. Embodiments are disclosed for broadcasting the auxiliary data during, immediately prior to and immediately following the broadcast of musical selections, without the need to use the SCA portion of the broadcast band.

Abstract: A warning radio receiver is adapted to receive not only a recognition signal for emergency broadcast but also two further recognition signals, namely a warning network transmitter recognition signal and a warning region recognition signal. If, for example, the currently tuned transmitter changes its warning region recognition signal, after the expiration of the timing period of a first timer 16, one or more seeking operations for other transmitters with the predetermined warning region recognition signal are started. If a predetermined number of such seeking operations remain unsuccessful, the reception readiness of the transmitter is demonstrated by switchover to a transmitter associated with a different warning region. If such other transmitters also cannot be found, exceeding another predetermined number of fruitless seeking operations results in the generation of a receiver malfunction indication.

Abstract: A method and system for the contemporaneous delivery of data from a first location to a user at a remote location utilizes standard broadcast facilities as the transmission medium. The data and an identifier uniquely associated with the data are encoded and transmitted along with a first standard broadcast signal. An enabling cue signal corresponding to the identifier is encoded and transmitted along with a second standard broadcast signal. The first broadcast signal is received and demodulated at the user location, the identifier is decoded and the encoded data is stored in a memory location uniquely associated with the identifier. The second standard broadcast signal is also received and demodulated at the user location and is decoded to provide the cue signal. The cue signal is compared with the received identifier and if the comparison is positive the stored encoded data is recalled from the memory, decoded and printed at the discretion of the user.

Abstract: A technique for broadcasting program material together with encoded items of information pertaining to the program material such as the title of a broadcast musical piece, the artist name, catalog number, and the like. A number of sources of recorded program material are provided at a broadcast site, and encoded information data pertaining to the program material is processed for transmission from the site with the broadcast program material. A receiver reproduces the program material and, upon entry of a memory command, decodes and stores the transmitted items of information data in a memory. Sets of stored information data relating to selected broadcasts can later be retrieved from the memory and output by a display and/or a printer device.

Abstract: A data communication system in which video data is digitized, compacted, and transmitted by a frequency modulated radio station having a subsidiary communication authorization. The data is broadcast on a subcarrier channel to a radio receiver, which is connected to a microcomputer. This microcomputer generates a visual graphic display on a screen, and performs various other functions, such as error checking and permitting the user to alter the display. One application of the invention is real time monitoring of visual information by a remote receiving station. Furthermore, the invention may include a receiver that is turnable, thereby providing data to a mobile receiving station, such as an airplane. Although the invention is especially useful for monitoring weather information, it is adaptable for use with any visual graphics data that is desired to be transmitted via FM subcarrier frequencies.

Abstract: An SCA receiver is provided which has a close to ideal passband characteristic which greatly improves frequency response to produce a brighter sound due to the use of ceramic resonator elements. The use of ceramic resonator elements and a superheterodyne approach also provides a receiver which can be rapidly aligned and which has improved noise protection, lower distortion, increased stability, less residual subcarrier in the audio, and more consistent performance from one unit to the next. In one embodiment the superheterodynes circuit operates at 455 kHz which up-converts the usual 67 kHz signal by mixing it with the output of a ceramic resonator controlled local oscillator/mixer. The ceramic resonator and ceramic filter along with the local oscillator/mixer I.C. provides low group delay, improved impulse noise rejection, while most importantly achieving at least an order of magnitude better audio response over the signal bandwidth.

Abstract: A facsimile signal control system adapted to be connected between a facsimile machine and a telephone line, comprises an RF signal receiver adapted to receive and demodulate RF signals from an antenna, a change-over switch, a first port for connection to a facsimile machine, and a second port for connection to a telephone line and an interface circuit. A control circuit is connected to apply the demodculated facsimile signals from the signal receiver to the interface circuit. The control means further comprises means for controlling the change-over switch to selectively connect the first port to either the second port or the interface circuit.

Abstract: Information is transmitted at microwave frequencies, the ground station being connected to a waveguide (25) and the station aboard a railway vehicle being connected to an antenna (26). Each station comprises a microwave generator (19) supplying a carrier, transmitters (3 through 7) supplying subcarriers, receivers (28 through 32) and a pilot generator (1). The carrier and subcarrier frequencies are multiples of the pilot frequency and the frequency difference between adjacent subcarriers equals the pilot frequency. A transmitter mixer (MTX) receives the carrier and the subcarriers and is connected to a circulator (24), itself linked to the waveguide (25) in the ground station and to the vehicle station antenna. A receiver mixer (MRX) is connected via a filter (23) to the circulator (24) and receives the carrier from the microwave generator; the latter mixer is connected to the receivers (28 through 32) to which it sends the subcarriers transmitted by the other station.

Abstract: A converter to convert audio signal associated with commercial television transmissions for input into conventional AM/FM automobile receivers so as to facilitate listening to the audio portions of telecasts on conventional radios.

Abstract: In a communication system for use in transmitting a sequence of information signals in addition to a sequence of digital voice signals subjected to adaptive delta modulation, the information signal sequence is modulated by a phase modulator (51) of the transmitter section (11a) into a phase modulated signal sequence and is combined with the digital signals by a combining circuit (15) into output signals. The phase modulated signals might be sent through an ADM decoder (36) and a switch (44) of a receiver section (12a) to a loudspeaker (45) to be reproduced together with the digital voice signals. However, such phase modulated signals are not substantially audible for listeners because the phase modulated signals scarcely comprise a low frequency component. The phase modulated signals may be binary Manchester code signals and may be either interposed in a quiescent time of the digital voice signals or placed at the end or beginning of each digital voice signal.

Abstract: A wristwatch FM subcarrier paging receiver architecture is disclosed that overcomes the many inherent problems (such as self-oscillation, image responses, spurious local oscillator radiation and interference from entertainment programming) that are encountered in this demanding application. The disclosed architecture includes a tunable notch filter front end, an image cancelling mixer, an automatic gain control circuit, a phase detector for linear detection, frequency feedback for distortion reduction, a synthesized local oscillator, and a frequency plan which can utilize both high and low side local oscillator injection to optimize performance in anticipated interference environments.

Abstract: An autombile radio capable of receiving VHF entertainment programs from a station in which traffic information signals are modulated in a 57 kHz subcarrier is equipped with two decoders for the 57 kHz subcarrier signals, one decoder for traffic information signals modulated in an analog fashion on the subcarrier and another decoder for digital signals modulated on that subcarrier by double-sideband suppressed-carrier modulation. The first decoder is for a system already in use in which traffic information, at least if urgent, is intended to override the entertainment program, and the receivier has the usual circuits for that override. The second decoder is for a system that is planned but not yet in use in which the received digital signals can call out one or more standard messages or message portions from a read-only memory and either the memory addresses or the memory outputs are storable.

Abstract: A transceiver and method of controlling the automatic retransmission of a radio frequency commmunications signal in which a pilot tone within the radio frequency communications channel bandwidth but above the band of frequencies necessary for intelligence is phase modulated at a frequency below the frequency band of the intelligence and combined with the intelligence for transmission over a first frequency communication link. When received, the presence of the pilot tone and the modulation is detected, compared with predetermined standards and utilized to control the application of the demodulated intelligence to a second communication link. After establishing the second communication link, the predetermined standards utilized to control the application of the intelligence to the second communication link are relaxed.

Abstract: A digital transmission system using standard FM broadcast stations employs an SCA subcarrier which is amplitude modulated with a second subcarrier modulated to have different phase orientations representative of digital data. Bits are separated from a digital data stream in groups and are differentially encoded into one of at least four phase orientations of the second subcarrier. The amplitude modulated SCA subcarrier is combined with the stereo signal output of a stereo multiplexer to form the modulating signal for the station FM modulator. The receiver includes a differential phase detector for reconstruction of the differentially encoded digital data.A system which additionally includes means for modulating the SCA subcarrier with a composite signal having an audio signal in addition to the differentially encoded second subcarrier is disclosed.

Abstract: An essentially digital circuit is disclosed in which a demodulated broadcast signal is digitized by an analog-to-digital converter and processed in three signal paths each including a tuned filter. The tuned filters have closely adjacent resonance frequencies, the same resonance curves, and the same resonance rises. The signals at the outputs of these three signal paths are so evaluated by means of four comparators and an RS flip-flop that the message tone signal appears at the Q output of the flip-flop only in the presence of the message tone frequency.

Abstract: FM transmission system in which, besides program content, an auxiliary carrier of, for example 57 kHz, is radiated, which auxiliary carrier is modulated by an announcement recognition (AR) signal and by a region or radio-station recognition (RR) signal, the AR and RR signals being low-frequency, AM modulations on the auxiliary carrier. To enhance recognition of an AR signal, e.g. between 142 and 170 Hz, is enhanced, in spite of reception difficulties, for example due to multi-path reception and the like, by decreasing the modulation of the 57 kHz subcarrier by the RR signal to 30% or less, while the AR signal is modulating the subcarrier, so that the AR modulation may extend to 60 and even 90% modulation. Multiple AR frequencies can be used, for example to characterize different announcements, e.g. in different languages, or of different characteristics, such as traffic, news, sports, or others, recognition of the AR signal in the receiver permitting switch-over from other reproduced programs, e.g.

Abstract: A circuit for decoding broadcast traffic area signals according to the European standards utilizes digital circuitry to check for four criteria.

Abstract: A single sideband communications system conveying a message through a transmitter to one or more predetermined receivers which are enabled by a coded squelch signal unique to the predetermined receivers is disclosed. The transmitter comprises means to angle modulate both the pilot signal and the information bearing single sideband signal with the coded signal at a predetermined deviation and to transmit the resulting signal.Each receiver frequency control means tracks the frequency excursions of a selected portion of the transmitted signal up to predetermined limits so that the message can be demodulated without frequency distortion being introduced. Each receiver demodulates the coded squelch without interfering with the message demodulation or tracking functions and activates the receiver squelch of those preselected receivers.

Abstract: Communication system for either public or private electric power load management and distribution automation, and the like, wherein subcarrier signals are sent to a plurality of remotely located receivers and transmitters using an existing standard FM broadcast station. The broadcast signal is detected by a receiver which filters out the subcarrier component of the broadcast signal. The radio frequencies of the plurality of remotely located transmitters and receivers are closely spaced and synthesized from the frequency of the broadcast subcarrier and their time of transmission, digital bit streams, and message frames are all synchronized from the subcarrier signal. The FM broadcast station thereby orchestrates all communication activity to and from the plurality of remote locations to optimize traffic flow and maximize a priori information to all components to significantly increase reliability.

Abstract: To monitor the operability of a radio receiver which has special recognition circuitry to recognize warning or emergency announcements, a modulation detector (11) is provided, sensing the change in degree of modulation of a region recognition (RR) signal, which changes its degree of modulation when an announcement recognition (AR) signal is radiated, the degree-of-modulation signal being stored in a memory (flip-flop 12), the output of which controls a transfer switch (6). The transfer switch transfers output from a muting stage (5) in the receiver, which is disabled upon detection of the AR frequency to a tone generator, for application to the amplifier of a warning tone if no change in the degree of modulation of the RR signal has been detected within a predetermined time period, as determined by a timing stage (15). A suitable timing interval is, for example, 24 hours. If such timing signals are received, the tone generator is not enabled, however.

Abstract: To decode control signals from a mixture of signals including audio signals, such as music, voice or speech, in which the control signals are within the audio range, for example 2,350 Hz, on which a low-frequency signal, for example in the 100-200 Hz range is modulated, the control signal in the form of a control tone is filtered and demodulated by band pass filters (1,3), demodulators and rectifiers (2,4), and then applied to a timing circuit (5) which provides an output signal if and only if the demodulated control tone is continuously applied during the timing interval thereof. Suitable timing intervals are about 1 second, to provide an output signal which can switch a flipflop (7) on, for example to command radiation of a particular type of recognition signal by the transmitter (13), the setting of the flipflop (FF) (7) being fed back to the timing circuit to change the timing interval thereof to a lesser amount, for example 1/2 seconds, to provide for a shorter signal to cause resetting of the FF (7).

Abstract: To permit simultaneous transmission of command codes, in binary command words, with traffic or other announcements, being broadcast over an FM transmitter which has a 57 kHz subcarrier AM modulated by an announcement recognition (AR) signal, for example 125 Hz, use is made of the long response time of AR switching elements to provide, before the AR switching element (13) can respond, decoding of a command word at a clock rate which is fast with respect to the response time of the long switching time constant switching element (13).

Abstract: To prevent loss of information during an announcement in a traffic or announcement recognition system in which, during radiation of an announcement, a subcarrier is modulated to a lesser degree by a radio station or region recognition frequency (RR) but to a higher degree by an announcement recognition (AR frequency) during an announcement only, and a logic circuit is included in the announcement decoder which recognizes(1) presence of an RR signal to tune the receiver to the station radiated, and(2) presence of an AR signal, the presence of the AR signal being sensed and utilized to inhibit re-tuning of the receiver even though the previously detected RR signal may no longer be detected by the receiver.

Abstract: To permit mass-production of coders selectively usable in various types of transmitter installations, and regardless of whether designed for stereophonic or monophonic transmission, in which a subcarrier of non-audible frequency (57 kHz) is radiated, amplitude modulated by separate recognition signals characterizing intelligence information (AR, or announcement recognition) and a specific transmitter (region or radio station recognition, RR), a memory element (36) such as a PROM is provided, connected to a selector switch, the memory element having stored therein data representative of(1) frequency of amplitude modulation of the subcarrier of the announcement recognition (AR) signal;(2) frequency of amplitude modulation of the radio station recognition (RR) signal;(3) degree of modulation by the (AR) signal;(4) degree of modulation by the (RR) signal, and,preferably, data to provide a visual indication of a respective frequency channel and modulation degree, the memory element (36) being programmed for select

Abstract: To 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 is essentially continuously modulated by region or radio-station recognition signals, the level of which changes when the announcement recognition signal is radiated, the subcarrier is filtered in the receiver, demodulated, and the degree of modulation by the frequency characteristics of the region or radio-station recognition frequency (RR) is sensed.

Abstract: Up to date television programming information along with a commercial is provided for a viewer of television independent of the viewer's television set. Such is accomplished by a radio either AM or FM which broadcasts first and second subcarrier signals carrying respectively a commercial and up to date television program information. The commercial and up to date television program information repeats after given set time periods, the later being updated every one-half hour. A viewer need only operate a specially designed radio receiver at a convenient location anytime he wishes to know which programs are coming up on his television set. The receiver is designed so that it will always play the broadcast commercial before the television program so that the system can be appropriately financed with no cost to the viewer.

Abstract: To 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.

Abstract: A capacitive signal dependent upon a quantity being measured is produced by capacitive sensors of a radiosonde. An oscillator in the radiosonde has an output frequency, controlled by the capacitive signal, in the order of 1 to 10 MHz. The output frequency of the oscillator is divided by a factor of 2.sup.7. A high frequency transmitter in the radiosonde is frequency modulated by a frequencyf.sub.M1 =f.sub.M0 /dwherein f.sub.M1 is the output frequency of the divider and f.sub.M0 is the input frequency of the divider.