Parallel digital data communications

• US 5,517,433 A
• Filed: 07/07/1994
• Issued: 05/14/1996
• Est. Priority Date: 07/07/1994
• Status: Expired due to Fees

• Current Assignee: Remote Intelligence Incorporated
• Original Assignee: Remote Intelligence Incorporated
• Inventors: Morrison, Robert E.
• Primary Examiner(s): Mai, Tan V.
• Application Number:
  US08/271,172
• Time in Patent Office: 677 Days
• Field of Search: 364/602, 375/37, 375/38, 375/41, 375/17, 375/259, 375/260, 375/268, 375/286, 370/69.1, 370/120, 370/123
• US Class Current: 708/3
• CPC Class Codes: H04L 27/12 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes H04L27/32 takes precedence
• CPC Class Codes: H04L 5/02 Channels characterised by the type of signal

Abstract

A method and apparatus for transmitting parallel digital data bit patterns over a single line is disclosed. Parallel digital data bit patterns are transformed into analog signals that are representative of the digital data bit patterns. Each digital data bit pattern is assigned an analog representation (either frequency, phase, or amplitude depending on the transmission medium). Each analog representation of the digital signal is then combined with a carrier signal and transmitted to the receiving end of the apparatus where the carrier signal is stripped off and the original analog signal transmitted is transformed into the original parallel digital data bit pattern transmitted.

Claims

1. A digital data transmission system for transmitting parallel digital data bit patterns over a single line, comprising:

a look-up table for associating a unique frequency with the parallel digital data bit pattern;

a digital data synthesizer driven by said look-up table for generating a digital representation of said frequency;

a digital to analog convertor operatively connected to said digital data synthesizer for generating said frequency from said digital representation;

a first mixer operatively connected to said digital to analog convertor for mixing said frequency and a carrier signal;

a transmitter operatively connected to said first mixer;

a receiver operatively connected to said transmitter;

a second mixer operatively connected to said receiver and a local signal 180 degrees out of phase with said carrier signal thereby removing said carrier signal and recovering said frequency; and

decoder means operatively connected to said second mixer for identifying and transforming said frequency into the digital data bit patterns transmitted.

2. The digital data transmission system of claim 1 wherein said decoder means comprises:

a plurality of filters operatively connected to said mixer;

a plurality of amplifiers operatively connected to said filters;

a plurality of comparators operatively connected to said amplifiers;

a plurality of encoders operatively connected to said comparators; and

a latch operatively connected to said encoders for generating the bit pattern transmitted.

3. The digital data transmission system of claim 1 wherein said decoder means comprises a surface acoustic wave device.

4. The digital data transmission system of claim 2 wherein said plurality of filters identify said frequency.

5. The digital data transmission system of claim 1 wherein said plurality of amplifiers boost said frequency.

6. An apparatus for transmitting parallel digital data bit patterns over a single line, comprising:

look-up means for determining a digital representation for each digital data bit pattern;

conversion means operatively connected to said look-up means for converting the digital representations to a unique frequency;

first mixing means operatively connected to said conversion means for combining said unique frequency and a carrier signal;

transmitter means operatively connected to said mixing means for transmitting said combined unique frequency and carrier signal;

receiving means operatively connected to said transmitter means for receiving said combined unique frequency and carrier signal;

second mixing means operatively connected to said receiving means and a local signal 180 degrees out of phase with said first carrier signal for stripping off said first carrier signal from said combined unique frequency and first carrier signal; and

decoding means operatively connected to said second mixing means for decoding said unique frequency signal to the parallel digital data bit patterns transmitted.

7. The apparatus for transmitting parallel digital data bit patterns of claim 6 wherein said conversion means comprises:

at least one digital data synthesizer operatively connected to said look-up means; and

at least one digital to analog convertor operatively connected to said digital data synthesizer.

8. The apparatus for transmitting parallel digital data bit patterns of claim 6 wherein said decoding means comprises:

a plurality of filters operatively connected to said mixer;

a plurality of amplifiers operatively connected to said filters;

a plurality of comparators operatively connected to said amplifiers;

a plurality of encoders operatively connected to said comparators;

a latch operatively connected to said encoders for generating the bit pattern transmitted.

9. A method of transmitting parallel digital data bit patterns over a single line, comprising the steps of:

assigning a digital representation to each of the parallel digital data bit patterns;

converting the digital representations to a unique frequency;

mixing said unique frequency and a carrier signal, thereby forming a mixed signal;

transmitting said mixed signal to a receiver, said receiver receiving said mixed signal;

removing said carrier signal from said mixed signal resulting in said unique frequency;

transforming said unique frequency of the removing step to the parallel digital data bit patterns transmitted.

10. A digital data transmission system for transmitting a parallel digital data bit pattern consisting of a first bit group of n bits and a second bit group of m bits over a single line, comprising:

(a) look up means for assigning a first frequency from a first frequency group of 2ⁿ frequencies to the first bit group and a second frequency from a second frequency group of 2^m frequencies to the second bit group, said look up means generating digital representations of said first frequency and said second frequency, said first frequency group being completely disjoint from said second frequency group;

(b) conversion means operatively connected to said look up means for converting the digital representations of said first frequency and said second frequency to said first frequency and said second frequency;

(c) first mixing means operatively connected to said conversion means for combining said first frequency and said second frequency and a carrier signal thereby producing a combined signal;

(d) transmitter means operatively connected to said mixing means for transmitting said combined signal;

(e) receiving means operatively connected to said transmitter means for receiving said combined signal;

(f) second mixing means operatively connected to said receiving means and a local signal 180 degrees out of phase with said carrier signal for stripping off said carrier signal from said combined signal thereby recovering said first frequency and said second frequency; and

(g) decoding means operatively connected to said second mixing means for decoding said first frequency and said second frequency to said first bit group and said second bit group and combining said first bit group and said second bit group into the parallel digital data pattern.

11. The digital data transmission system of claim 10, wherein the parallel digital data bit pattern comprises eight bits and said first bit group and said second bit group each comprise four bits of said parallel digital data bit pattern.

12. The digital data transmission system of claim 10, wherein said conversion means comprises:

a first digital data synthesizer operatively connected to said look up means for generating a digital representation of said first frequency and a second digital data synthesizer operatively connected to said look up means for generating a digital representation of said second frequency; and

at least one digital to analog convertor operatively connected to said first digital data synthesizer and said second digital data synthesizer.

13. The digital data transmission system of claim 10, wherein said decoding means comprises:

a plurality of filters operatively connected to said mixer;

a plurality of amplifiers operatively connected to said filters;

a plurality of comparators operatively connected to said amplifiers;

a plurality of encoders operatively connected to said comparators; and

a latch operatively connected to said encoders for generating the bit pattern transmitted.

14. A digital data transmission system for transmitting a parallel digital data bit pattern over a single line, comprising:

a digital to analog converter generating a data frequency amplitude-modulated by the parallel digital data bit pattern;

an oscillator generating a clock frequency;

an amplifier operatively connected to said digital to analog convertor and said oscillator, said amplifier amplifying the data frequency and the clock frequency;

a transmitter operatively connected to said amplifier;

a receiver operatively connected to said transmitter;

a data filter operatively connected to said receiver, said data filter being responsive to said data frequency;

a clock filter operatively connected to said receiver, said clock filter being responsive to said clock frequency;

a data amplifier operatively connected to said data filter; and

an analog to digital convertor operatively connected to said data amplifier, said analog to digital convertor converting the amplitude of said data frequency to the parallel digital data bit pattern.

15. The digital data transmission system of claim 14, wherein each value of the parallel digital data pattern causes said data frequency to be modulated to a unique amplitude.

16. The digital data transmission system of claim 14, wherein the value range of the parallel digital data pattern comprises a plurality of value groups, each value within each value group causing said data frequency to be modulated to a unique amplitude, and wherein the amplitude of said clock frequency identifies the value group being transmitted and received.