Two-way transmission system for ground/mobile station communications
First Claim
1. A two-way information transmission system for communications between a ground control station connected to a waveguide and a vehicular mobile station connected to an antenna moving alongside the waveguide, each of said ground and mobile stations comprising a transmitter-receiver unit, the ground station transmitting in a higher frequency band than said vehicular station, wherein each transmitter-receiver unit comprises a pilot signal generator supplying a pilot frequency, a microwave generator supplying a carrier at a frequency that is a multiple of the pilot frequency, a coupler with input connected to the microwave generator, one output connected to a transmitter mixer and another output connected to a receiver mixer, transmitter circuits each connected to the pilot generator and each supplying a subcarrier at a frequency which is a multiple of the pilot frequency, the subcarriers having different, evenly spaced frequencies, the difference between successive subcarrier frequencies being equal to the pilot frequency and the frequencies of the subcarriers being less than the frequency of the carrier, a transmission coupler input-connected to the transmitter circuits and output-connected to the transmitter mixer, a circulator connected to the waveguide, to the transmitter mixer and, via a filter, to the receiver mixer, and a receiver coupler with an input connected to the receiver mixer and output connected to receivers to which it routes subcarriers that it receives from the waveguide via the receiver mixer.
1 Assignment
0 Petitions
Accused Products
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.
35 Citations
9 Claims
- 1. A two-way information transmission system for communications between a ground control station connected to a waveguide and a vehicular mobile station connected to an antenna moving alongside the waveguide, each of said ground and mobile stations comprising a transmitter-receiver unit, the ground station transmitting in a higher frequency band than said vehicular station, wherein each transmitter-receiver unit comprises a pilot signal generator supplying a pilot frequency, a microwave generator supplying a carrier at a frequency that is a multiple of the pilot frequency, a coupler with input connected to the microwave generator, one output connected to a transmitter mixer and another output connected to a receiver mixer, transmitter circuits each connected to the pilot generator and each supplying a subcarrier at a frequency which is a multiple of the pilot frequency, the subcarriers having different, evenly spaced frequencies, the difference between successive subcarrier frequencies being equal to the pilot frequency and the frequencies of the subcarriers being less than the frequency of the carrier, a transmission coupler input-connected to the transmitter circuits and output-connected to the transmitter mixer, a circulator connected to the waveguide, to the transmitter mixer and, via a filter, to the receiver mixer, and a receiver coupler with an input connected to the receiver mixer and output connected to receivers to which it routes subcarriers that it receives from the waveguide via the receiver mixer.
Specification