|
PatentVote.com: Vote on your favourite invention!
|
|
 |
Title: Transmission device of a radiographic navigation system
Claims: What is claimed is: 1. A transmission device of a radiographic navigation system for azimuth determination, in which the transmission device generates a rotating directional beam pattern and a static, omnidirectional phase reference beam pattern, comprising a carrier wave generator and a modulation signal generator, two double sideband modulators which are connected to the two generators and which serve to generate, for the benefit of the rotating directional beam pattern, two double sideband signals having a modulation which is phase-shifted 90.degree. with respect to each other and a suppressed carrier wave, two transistorized power amplifiers, each of which is coupled to one of the modulators, and a phase reference signal generator which is coupled to the carrier wave generator and the modulation signal generator for generating a phase reference signal for the benefit of the static beam pattern, a phase comparison device including a mixing signal generator and three mixing devices which are coupled thereto, each mixing device being coupled to an output of the power amplifiers and the phase reference signal generator for transposing the carrier wave frequencies of the double sideband signals and the phase reference signal to a lower frequency, two modulation eliminators which are provided with control inputs and each of which is coupled to an output of the mixing devices which supply the frequency-transposed double sideband signals, the control inputs being coupled to the modulation signal generator for eliminating the frequency-transposed double sideband signals, and two phase discriminators, each of which is coupled to one of the modulation eliminators, both phase discriminators being coupled, via a modulation eliminator, to the mixing device which supplies the frequency-transposed phase reference signal, and two phase shifters which have control inputs and which are each included in one of the signal paths of the double sideband signals, the control inputs being coupled to the phase discriminators for controlling the phase of the double sideband signals under the control of control signal supplied by the phase discriminators. 2. A transmission device as claimed in claim 1, wherein two differential amplifiers are included, each first input thereof being connected to one of the phase discriminators and each second input thereof being connected to a potentiometer, each of the outputs thereof being connected to a control input of the phase shifters. 3. A transmission device as claimed in claim 1, wherein each modulator comprises the series connection of a phase reversal modulator and an amplitude modulator and in which the phase reversal modulator is connected to the modulation signal generator via a signal zero-crossing detector, the amplitude modulator being connected to the modulation signal generator via a full-wave rectifier, and each modulation eliminator comprises the series connection of an amplitude eliminator and a phase reversal eliminator, the phase reversal eliminator being provided with control inputs which are connected to the zero-crossing detectors. 4. A transmission device as claimed in claim 3, wherein the amplitude eliminator is a change-over switch. 5. A transmission device as claimed in claim 1, wherein the frequency of the mixing signal generator is 135 KHz. Other info: Inventors: van den Berg, Frederik Louis (Hilversum, NL) Application Number: 574103 Filing Date: 1975-05-02 Publication_date: 1976-09-07 Assignee: U.S. Philips Corporation (New York, NY) Primary Class(es): 342/404 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Wilbur, Maynard R. Assistant Examiner: Blum, T. M. Attorney: Trifari; Frank R., Berka; George B. |
|