Apparatus and method for digital information transfer

• US 6,122,323 A
• Filed: 03/23/1998
• Issued: 09/19/2000
• Est. Priority Date: 08/02/1994
• Status: Expired due to Fees

• Current Assignee: International Automated Systems
• Original Assignee: International Automated Systems
• Inventors: Johnson, Neldon P.
• Primary Examiner(s): Ghebretinsae, Temesghen
• Application Number:
  US09/043,478
• Time in Patent Office: 911 Days
• Field of Search: 375/259, 375/260, 375/295, 375/350, 375/316, 370/442, 370/522, 370/458, 370/498, 455/59
• US Class Current: 375/259
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

A method and apparatus for multiple frequency, multiple channel digital information transfer through time slot allocation. The apparatus consists of one or more transmitting devices and one or more receiving devices. Multiple source signals are each allocated a time slot and a frequency. A continuous synchronizing wave defines the time slots and provides for time slot tracking. Digital signals from each source are allocated a time slot and assigned one of the information wave frequencies in that time slot. The information waves are combined with the synchronizing wave and transmitted to one or more receivers as one signal in each time slot. The manner in which the waves are combined allows the components to be extracted by the receivers largely through the use of curve fitting techniques rather than through the use of filters. The output digital signals can be calibrated through the use of a synchronization wave with a reference amplitude or through the use of one or more of the information waves as a reference.

Claims

1. An apparatus for digital information transfer comprising:

a) means for generating a continuous synchronizing wave of a selected wave form and frequency;

b) means for allocating a plurality of source digital signals to unique, repetitive time slots, one or more source digital signals being allocated simultaneously to each time slot, the time duration of said time slots being defined by one complete cycle of the synchronizing wave, and each time slot being cycled at a selected frequency;

c) means for generating an analog information wave for each said source digital signal, each said information wave comprising a complete cycle of a selected wave form and each information wave generated in each time slot having a frequency which is distinct from the frequency of the other information waves generated simultaneously in the same time slot, each information wave having a frequency which is greater than the frequency of the synchronizing wave and having a start position which coincides with the start of the time slot, and the amplitude of each information wave being a function of the magnitude of the corresponding source digital signal as measured during the allocated time slot for the signal;

d) means for combining each analog information wave generated in each time slot and the synchronizing wave to form a combined wave for each time slot;

e) means for transmitting each combined wave within the allocated time slot;

f) means for receiving at one or more locations each combined wave within the allocated time slot;

g) means for extracting the synchronizing wave and information wave components of each received combined wave;

h) means for determining the amplitude of each extracted information wave for each time slot; and

i) means for generating an output digital signal for each information wave extracted in each time slot, said output digital signal having a digital magnitude which is a function of the amplitude of the corresponding received information wave.

2. An apparatus as claimed in claim 1 further comprising a means for calibrating each output digital signal.

3. An apparatus as claimed in claim 1 further comprising a means for generating the synchronizing wave at a selected amplitude and a means for calibrating the output digital values by comparing the amplitude of the extracted sychronizing wave as received with the amplitude of the synchronizing wave as generated.

4. An apparatus as claimed in claim 1 wherein a plurality of cycles of the synchronizing wave are used to define the time slots.

5. An apparatus as claimed in claim 1 further comprising a means for generating a second synchronizing wave of a different frequency than the sychronizing wave, said second synchronizing wave frequency being selected to provide for repetitive zero matches between the synchronizing wave and the second synchronizing wave after a desired number of cycles of the synchronizing wave for each cycle of the time slots, a means for combining said second synchronizing wave with the synchronizing wave and information waves for transmission and a means for extracting the second synchronizing wave as received and tracking the cycles of the time slots.

6. An apparatus as claimed in claim 1 further comprising a means for generating one or more information waves at a selected reference amplitude and a means for calibrating the output digital signals by comparing the amplitude of these information waves as received with the known amplitude of these information waves as transmitted.

31. An apparatus as claimed in claim 1 further comprising a means for adjusting the amplitude of the combined wave to a desired signal level before transmission.

7. An apparatus for digital information transfer comprising:

a) means for generating a continuous synchronizing wave of a selected wave form and frequency;

b) means for allocating a plurality of source digital signals to unique, repetitive time slots, one or more source digital signals being allocated simultaneously to each time slot, the time duration of said time slots being defined by one complete cycle of the synchronizing wave, and each time slot being cycled at a selected frequency;

c) means for generating an analog information wave for each said source digital signal, each said information wave comprising a complete cycle of a selected wave form and each information wave generated in each time slot having a frequency which is distinct from the frequency of the other information waves generated simultaneously in the same time slot, each information wave having a frequency which is greater than the frequency of the synchronizing wave and having a start position in the time slot which is no earlier than the start position of any information wave with a lower frequency and having a stop position which is no later than the stop position of any information wave with a lower frequency, and the amplitude of each information wave being a function of the magnitude of the corresponding source digital signal as measured during the allocated time slot for the signal;

d) means for combining each analog information wave generated in each time slot and the synchronizing wave to form a combined wave for each time slot;

e) means for transmitting each combined wave within the allocated time slot;

f) means for receiving at one or more locations each combined wave within the allocated time slot;

g) means for extracting the synchronizing wave and information wave components of each received combined wave;

h) means for determining the amplitude of each extracted information wave for each time slot; and

i) means for generating an output digital signal for each information wave extracted in each time slot, said output digital signal having a digital magnitude which is a function of the amplitude of the corresponding received information wave.

8. An apparatus as claimed in claim 7 further comprising a means for calibrating each output digital signal.

9. An apparatus as claimed in claim 7 further comprising a means for generating the synchronizing wave at a selected amplitude and a means for calibrating the output digital values by comparing the amplitude of the extracted sychronizing wave as received with the amplitude of the synchronizing wave as generated.

10. An apparatus as claimed in claim 7 wherein a plurality of cycles of the synchronizing wave are used to define the time slots.

11. An apparatus as claimed in claim 7 further comprising a means for generating a second synchronizing wave of a different frequency than the sychronizing wave, said second synchronizing wave frequency being selected to provide for repetitive zero matches between the synchronizing wave and the second synchronizing wave after a desired number of cycles of the synchronizing wave for each cycle of the time slots, a means for combining said second synchronizing wave with the synchronizing wave and information waves for transmission and a means for extracting the second synchronizing wave as received for tracking the cycles of the time slots.

12. An apparatus as claimed in claim 7 wherein the means for generating the information waves generates each of the waves with its mid cycle point at the midpoint of the time slots.

32. An apparatus as claimed in claim 7 further comprising a means for adjusting the amplitude of the combined wave to a desired signal level before transmission.

13. A method for digital information transfer comprising the steps of:

a) generating a continuous synchronizing wave of a selected wave form and frequency;

b) allocating a plurality of source digital signals to unique, repetitive time slots, one or more source digital signals being allocated simultaneously to each time slot, the time duration of said time slots being defined by one complete cycle of the synchronizing wave, and each time slot being cycled at a selected frequency;

c) generating an analog information wave for each said source digital signal, each said information wave comprising a complete cycle of a selected wave form and each information wave generated in each time slot having a frequency which is distinct from the frequency of the other information waves generated simultaneously in the same time slot, each information wave having a frequency which is greater than the frequency of the synchronizing wave and having a start position which coincides with the start of the time slot, and the amplitude of each information wave being a function of the magnitude of the corresponding source digital signal as measured during the allocated time slot for the signal;

d) combining each analog information wave generated in each time slot and the synchronizing wave to form a combined wave for each time slot;

e) transmitting each combined wave within the allocated time slot;

f) receiving at one or more locations each combined wave within the allocated time slot;

g) extracting the synchronizing wave and information wave components of each received combined wave;

h) determining the amplitude of each extracted information wave for each time slot; and

i) generating an output digital signal for each information wave extracted in each time slot, said output digital signal having a digital magnitude which is a function of the amplitude of the corresponding received information wave.

14. A method as claimed in claim 13 further comprising calibrating each output digital signal.

15. A method as claimed in claim 13 further comprising generating the synchronizing wave at a selected amplitude and calibrating the output digital values by comparing the amplitude of the extracted sychronizing wave as received with the amplitude of the synchronizing wave as generated.

16. A method as claimed in claim 13 wherein a plurality of cycles of the synchronizing wave are used to define the time slots.

17. A method as claimed in claim 13 further comprising generating a second synchronizing wave of a different frequency than the sychronizing wave, said second synchronizing wave frequency being selected to provide for repetitive zero matches between the synchronizing wave and the second synchronizing wave after a desired number of cycles of the synchronizing wave for each cycle of the time slots, combining said second synchronizing wave with the synchronizing wave and information waves for transmission and extracting the second synchronizing wave as received for tracking the cycles of the time slots.

18. A method as claimed in claim 13 further comprising generating one or more information waves at a selected reference amplitude and calibrating the output digital signals by comparing the amplitude of these information waves as received with the known amplitude of these information waves as transmitted.

33. A method as claimed in claim 13 further comprising a step of adjusting the amplitude of the combined wave to a desired signal level before transmission.

19. A method for digital information transfer comprising the steps of:

a) generating a continuous synchronizing wave of a selected wave form and frequency;

b) allocating a plurality of source digital signals to unique, repetitive time slots, one or more source digital signals being allocated simultaneously to each time slot, the time duration of said time slots being defined by one complete cycle of the synchronizing wave, and each time slot being cycled at a selected frequency;

c) generating an analog information wave for each said source digital signal, each said information wave comprising a complete cycle of a selected wave form and each information wave generated in each time slot having a frequency which is distinct from the frequency of the other information waves generated simultaneously in the same time slot, each information wave having a frequency which is greater than the frequency of the synchronizing wave and having a start position in the time slot which is no earlier than the start position of any information wave with a lower frequency and having a stop position which is no later than the stop position of any information wave with a lower frequency, and the amplitude of each information wave being a function of the magnitude of the corresponding source digital signal as measured during the allocated time slot for the signal;

d) combining each analog information wave generated in each time slot and the synchronizing wave to form a combined wave for each time slot;

e) transmitting each combined wave within the allocated time slot;

f) receiving at one or more locations each combined wave within the allocated time slot;

g) extracting the synchronizing wave and information wave components of each received combined wave;

h) determining the amplitude of each extracted information wave for each time slot; and

i) generating an output digital signal for each information wave extracted in each time slot, said output digital signal having a digital magnitude which is a function of the amplitude of the corresponding received information wave.

20. A method as claimed in claim 19 further comprising calibrating each output digital signal.

21. A method as claimed in claim 19 further comprising generating the synchronizing wave at a selected amplitude and calibrating the output digital values by comparing the amplitude of the extracted sychronizing wave as received with the amplitude of the synchronizing wave as generated.

22. A method as claimed in claim 19 wherein a plurality of cycles of the synchronizing wave are used to define the time slots.

23. A method as claimed in claim 19 further comprising generating a second synchronizing wave of a different frequency than the sychronizing wave, said second synchronizing wave frequency being selected to provide for repetitive zero matches between the synchronizing wave and the second synchronizing wave after a desired number of cycles of the synchronizing wave for each cycle of the time slots, combining said second synchronizing wave with the synchronizing wave and information waves for transmission and extracting the second synchronizing wave as received for tracking the cycles of the time slots.

24. A method as claimed in claim 19 wherein the step of generating the information waves includes generating each of the waves with its mid cycle point at the midpoint of the time slots.

34. A method as claimed in claim 19 further comprising a step of adjusting the amplitude of the combined wave to a desired signal level before transmission.

25. An apparatus for digital information transfer comprising:

a) a transmission apparatus comprising

(1) a digital input storage device which stores input digital source signals for release during allocated, repetitive time slots for the signals;

(2) a wave synthesizer which receives one or more input digital signals from the digital input storage device during each time slot and converts each of them to an information wave of a selected wave form with a different assigned frequency and an amplitude determined by an algorithm based upon the magnitude of the corresponding digital inputs, said information waves having a start position in the time slot which is no earlier than the start position of any information wave with a lower frequency and having a stop position which is no later than the stop position of any information wave with a lower frequency;

(3) a wave adder circuit which combines each of the information waves in each time slot and adds a continuous synchronizing wave of a selected waveform and frequency to the combined information waves to form a combined wave, said synchronizing wave having a lower frequency than the lowest frequency information wave and one cycle of said synchronizing wave defining the time duration of said time slots;

(4) a wave memory device which stores the combined waves until a pre-set number of waves have been stored;

(5) transmitter control circuits which determine when the combined waves in each time slot are to be released for transmission; and

(6) a transmitter to transmit the time-slotted combined wave to one or more receiving devices, and

b) a receiving apparatus at one or more locations comprising

(1) a pre-amp circuit which amplifies the received combined wave;

(2) a primary sync filter circuit for separating out the synchronizing wave from the combined wave for use in controlling the pre-amp circuit;

(3) an automatic gain control circuit which controls the level of pre-amplification based upon the amplitude of the synchronizing wave as received;

(4) an analog to digital conversion circuit which digitizes each pre-amplified combined wave as it is received;

(5) a memory circuit which stores the digitized combined wave from each time slot;

(6) one or more control circuits which extract the sychronizing wave component and each of the information wave components of the digitized combined wave in each time slot and generate output digital signals for each time slot which are a function of the amplitude of the extracted information waves through use of the known algorithm which was used by the transmission apparatus to generate the information waves.

26. An apparatus as claimed in claim 25 wherein the wave synthesizer generates all said information waves with a start position at the beginning of their time slot.

27. An apparatus as claimed in claim 25 wherein the wave synthesizer generates all said information waves with their mid cycle point centered at the mid point of the time slots.

28. An apparatus as claimed in claim 25 further comprising a counter circuit, which tracks the time slots and determines when a time slot cycle ends and another commences.

29. An apparatus as claimed in claim 25 wherein the receiving apparatus further comprises a counter circuit, which tracks the time slots and determines when a time slot cycle ends and another commences, and wherein the wave synthesizer in the transmission apparatus generates a second synchronizing wave with a frequency which is different from the frequency of the synchronizing wave and this second synchronizing wave is added to the synchronizing wave and the information waves and is thus included in the transmitted combined wave, and wherein the receiving apparatus further comprises a second sync filter circuit which separates the second synchronizing wave from the combined wave, a discriminator which compares the two synchronizing waves in each time slot, and when they experience a zero match the discriminator signals the counter to reset for a new time slot cycle, the frequency of said second synchronizing wave being adjusted to provide for a zero match between the two waves each time the sychronizing wave and the time slots go through a selected number of cycles.

30. An apparatus as claimed in claim 25 wherein the wave adder circuit also compares the amplitude of the combined wave with a check wave of a selected amplitude and adjusts the amplitude of the combined wave before transmission.