ALL DIGITAL DISTANCE MEASURING EQUIPMENT

• US 3,680,097 A
• Filed: 10/28/1969
• Issued: 07/25/1972
• Est. Priority Date: 10/28/1969
• Status: Expired due to Term

• Current Assignee: Dean P. Huntsinger
• Original Assignee: Dean P. Huntsinger
• Inventors: Huntsinger, Dean P.
• Primary Examiner(s): Hubler, Malcolm F.
• Application Number:
  US04/870,026
• Time in Patent Office: 1,001 Days
• Field of Search: 343/5DP,7.3
• US Class Current: 342/47
• CPC Class Codes: G01S 13/16 using counters
• CPC Class Codes: G01S 13/70 for range tracking only
• CPC Class Codes: G01S 13/785 Distance Measuring Equipment [DME] systems

Abstract

This invention relates to all-digital distance-measuring radio equipment wherein all time measurements are performed by counting oscillator pulses, and a single counter performs both search and memory functions while yielding directly readable distance values.

Claims

1. An all-digital DME system comprising:

a pulse generator, transmitter means connected to receive pulses from said pulse generator and responsive thEreto to transmit an interrogation signal, a clock oscillator, a control counter operative to generate a first signal upon completion of a first train of clock pulses defining a predetermined time interval and to generate a second signal upon completion of a second train of clock pulses corresponding to the maximum range of said system, distance gate means operable to pass said clock pulses, clock gate means connected to receive pulses from said pulse generator and said first and second signals from said control counter and responsive to pulses from said pulse generator to pass clock pulses from said clock oscillator to said control counter and responsive to said first signal from said control counter to pass said clock pulses to said distance gate and upon receipt of said second signal to discontinue passage of said clock pulses to said control counter and said distance gate, range gate means operable to pass a range gate signal to said distance gate means and to cause said distance gate to halt passage of said clock pulses upon discontinuance of said range gate signal, distance counter means connected to receive said clock pulses from said distance gate means and operative upon reaching a first predetermined count to cause said range gate means to initiate said range gate signal and operative upon reaching a second predetermined count to cause said range gate means to discontinue said range gate signal, receiver means for receiving reply signals and responsive thereto to pass a signal to said distance gate to cause said distance gate to pass said clock pulses to said distance counter, and logic circuit means connected to receive said range gate signal and said reply signal and operative upon receipt of said reply signal during receipt of said range gate signal to pass a signal to said distance gate to cause said distance gate means to continue to pass said clock pulses to said distance counter following discontinuance of said range gate signal.

2. The apparatus of claim 1 wherein:

said clock oscillator emits clock pulses spaced in time intervals corresponding to the travel time of radio signals over a predetermined distance.

3. The apparatus of claim 1 wherein:

said clock oscillator emits clock pulses at a frequency of 809 KHz.

4. The apparatus of claim 1 wherein:

said predetermined time interval defined by said first series of clock pulses counted by said control counter is slightly less than 50 microseconds.

5. The apparatus of claim 1 wherein:

said control counter generates said first signal upon counting 24 clock pulses in said first train.

6. The apparatus of claim 1 further comprising:

readout means, and means included in said distance gate and responsive to receipt by said distance gate of said signal from said logic circuit means to cause said distance counter upon completion of the cycle of operation to apply to said readout means a signal indicative of the count held by said distance counter.

7. The apparatus of claim 1 further comprising:

offset circuit means interposed between said clock gate and said distance gate operative during the second and subsequent cycles of search mode operation of said system to block passage of a predetermined number of clock pulses from said clock gate to said distance gate.

8. The apparatus of claim 7 wherein:

said predetermined number of clock pulses is equal to one-half of the width of the range gate signal.

9. The apparatus of claim 7 wherein:

said predetermined number of clock pulses is four.

10. The apparatus of claim 1 wherein:

said distance counter is an Up-Down counter.