Dual-mode transmitter for railroad crossings
First Claim
1. An apparatus for use at railroad crossings comprising:
- a control receiver for detecting activation and completion signals from a control transmitter;
a multi-signal generator for simultaneously providing a plurality of signals within a portion of a selected frequency band and having a center frequency and relative frequency spacing of said simultaneous plurality of signals, wherein said multi-signal generator is a variable multi-signal generator for selectively adjusting said center frequency to cause said plurality of signals to cover a differing of the selected frequency band;
a modulator connected to said multi-signal generator for selectively and simultaneously modulating said plurality of signals;
a control unit for selectively controlling said multi-signal generator center frequency; and
wherein the transmitter begins transmission upon receipt of the activation signal and ceases transmission upon receipt of the completion signal.
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Accused Products
Abstract
A transmitter receivable by broadcast band receivers in nearby vehicles, comprising a first signal generator for simultaneously providing a plurality of selectively spaced carriers having frequency spacings corresponding to the individual channels of the band to be covered and selectively providing amplitude modulation when used for the AM broadcast band, and a second signal generator providing an FM modulated signal, which when combined with the signal from the first signal generator, covers various portions of the FM broadcast band to provide complete coverage thereof. A plurality of signals are generated in a portion of a selected band and modulated, according to the selected band mode, with a pre-stored and selectable voice alarm message.
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Citations
23 Claims
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1. An apparatus for use at railroad crossings comprising:
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a control receiver for detecting activation and completion signals from a control transmitter;
a multi-signal generator for simultaneously providing a plurality of signals within a portion of a selected frequency band and having a center frequency and relative frequency spacing of said simultaneous plurality of signals, wherein said multi-signal generator is a variable multi-signal generator for selectively adjusting said center frequency to cause said plurality of signals to cover a differing of the selected frequency band;
a modulator connected to said multi-signal generator for selectively and simultaneously modulating said plurality of signals;
a control unit for selectively controlling said multi-signal generator center frequency; and
wherein the transmitter begins transmission upon receipt of the activation signal and ceases transmission upon receipt of the completion signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 21, 22, 23)
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12. A dual-mode transmitter for use at railroad crossing, comprising:
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a first signal generator for simultaneously providing a plurality of carrier signals within a frequency band and having a relative frequency spacing, and including an amplitude modulator of said plurality of said plurality of signals according to a modulation signal;
a second signal generator for selectively providing a selectable frequency signal, and including a frequency modulator of said selectable frequency according to a modulation signal;
a mixer receiving the output signals of said first and second signal generators, and providing an output signal;
a power amplifier for selectively receiving said signals corresponding to said plurality of signals from said first signal generator and said mixer output signal, providing a signal to an antenna according to said selectively received signal;
a control means for selectably enabling said first signal amplitude modulator in a first mode, and said second signal generator frequency modulator in a second mode; and
means for detecting an activation signal and a completion signal; and
means for activating the dual-mode transmitter in response to receipt of the activation signal and for deactivating the dual-mode transmitter in response to receipt of the completion signal. - View Dependent Claims (13, 14, 15)
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16. A method for transmitting an alert of an approaching locomotive, the method comprising the steps of:
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sending, by a control transmitter located on the locomotive, an activation signal to a control receiver;
activating, by a control module operatively interconnected with the control receiver, a dual-mode transmitter adapted to transmit a warning message across one or more broadcast bands;
deactivating, by the control module upon receipt of a completion signal from the control transmitter, the dual-mode transmitter - View Dependent Claims (17, 18)
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19. An apparatus for use at railroad crossings comprising:
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a control receiver;
a multi-signal generator;
a modulator connected to said multi-signal generator;
for selectively and simultaneously modulating said plurality of signals;
a control unit;
for selectively controlling said multi-signal generator center frequency; and
wherein the multi-signal generator simultaneously provides a plurality of signals within a portion of a selected frequency band and having a center frequency and relative frequency spacing of said simultaneous plurality of signals and wherein said multi-signal generator is a variable multi-signal generator for selectively adjusting said center frequency to cause said plurality of signals to cover a differing of the selected frequency band. wherein the transmitter begins transmission upon receipt of the activation signal and ceases transmission upon receipt of the completion signal. - View Dependent Claims (20)
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Specification