Binary phase shift keying modulation system and/or frequency multiplier

• US 5,265,120 A
• Filed: 03/11/1992
• Issued: 11/23/1993
• Est. Priority Date: 08/27/1990
• Status: Expired

• Current Assignee: Globalstar Incorporated, M&FC Holding, LLC (Xylem, Inc.)
• Original Assignee: Axonn LLC (Globalstar Incorporated)
• Inventors: Sanderford, Hugh B. Jr.
• Primary Examiner(s): CAIN, DAVID C
• Application Number:
  US07/850,692
• Time in Patent Office: 622 Days
• Field of Search: 375/1, 375/67, 375/56, 375/83, 332/103
• US Class Current: 375/130
• CPC Class Codes: H03B 19/14 by means of a semiconductor device
• CPC Class Codes: H03C 1/545 using bipolar transistors
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04L 27/2057 with a separate carrier for each phase state
• CPC Class Codes: H04L 27/206 using a pair of orthogonal carriers, e.g. quadrature carriers

Abstract

A low cost spread spectrum modulator for BPSK, or Binary Phase Shift Keying capable of outputting the high modulation rate and suppressed carrier output needed in spread spectrum systems. The present invention provides high quality BPSK modulation without the double balance mixers as required in the prior art, thereby dispensing with the necessity of complex transistor/potonciometer or diode/transformer arrangements. The present invention provides BPSK modulation utilizing only one transformer, which can be adjusted for carrier suppression and two transistors, FET'"'"'s, or digital logic gates or the like, allowing the present system to be driven from low power CMOS logic levels, yet producing eight db of gain. The present invention may also be utilized as a frequency multiplier, with the utilization of the appropriately high frequency transistor, FET, digital logic gate, or the like.

Claims

1. A BPSK Modulator circuit, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means having first and second leg outputs, said transformer configured such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

first and second phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said first and second phase selection means further comprising first and second load transistors or their equivalent, respectively, each having an emitter, and a base or the equivalent, said base of said first transistor in circuit with said first output of said second inductor, receiving said "MOD +", said base of said second transistor in circuit with said second output of said second inductor, receiving said "MOD -".

2. A BPSK Modulator circuit having a tunable slug or core to adjust carrier suppression in a spread spectrum system, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means having first and second leg outputs, and a tunable slug or core in communication with said first and second induction means, said transformer configured such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

first and second phase selection means configured to modulate via input of said first and second leg outputs of said second induction means, said first and second phase selection means further comprising first and second load transistors, respectively, each having an emitter, a collector, and a base, said base of said first transistor in circuit with said first output leg of said second inductor, receiving said "MOD +", said base of said second transistor in circuit with said second output leg of said second inductor, receiving said "MOD -".

3. A BPSK Modulator circuit utilizing a loosely coupled transformer to adjust carrier suppression in a spread spectrum system, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means loosely coupled with said first induction means, said second induction means having first and second leg output, said transformer configured such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

first and second capacitors, said first capacitor in parallel circuit with said carrier input leg and grounded output leg of said first induction means, said second capacitor in parallel circuit with said first and second leg outputs of said second induction means,

first and second phase selection means configured to modulate via input of said first and second outputs of said second induction means, said first and second phase selection means further comprising first and second load transistors, respectively, each having an emitter, a collector, and a base, said base of said first transistor in serial circuit with said first leg output of said second inductor, receiving said "MOD +", said base of said second transistor in serial circuit with said second leg output of said second inductor, receiving said "MOD -".

4. The BPSK Modulation System of claim 3, wherein there is further included a tunable slug or core is in communication with said first and second inductors.

5. The BPSK Modulation System of claim 4, wherein there is further included resonator capacitor means in parallel circuit with said first and said second leg outputs of said second induction means, said resonator capacitor transformer coupling means configured to provide band pass filtering for previous stage harmonic suppression.

30. The BPSK modulation System as set forth in claim 3, further including a fixed transformer and a variable tuning capacitor, said fixed transformer in communication with said first and second induction means.

6. A BPSK Modulator circuit having a tightly coupled transformer having no center tap and a single parallel resonate capacitor on the secondary to provide BPSK modulation, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means tightly coupled to said first induction means, said second induction means having first and second leg outputs, said transformer configured such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

band pass filter means for filtering harmonic suppression from said transformer, said band pass filter means further comprising a resonate capacitor in parallel circuit with said first and second leg outputs of said second induction means;

first and second phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said first and second phase selection means further comprising first and second load transistors, respectively, each having an emitter, a collector, and a base, said base of said first transistor in circuit with said first leg output of said second inductor, receiving said "MOD +", said base of said second transistor in circuit with said second output of said second inductor, receiving said "MOD -".

7. The BPSK Modulation System of claim 6, wherein said system further comprises adjustment means for adjusting carrier suppression, said adjustment means further comprising a tunable slug or core in communication with said first and second induction means.

8. The BPSK Modulation System of claim 6, wherein there is further included resonator capacitor means in parallel circuit with said first and said second leg outputs of said second induction means, said resonator capacitor means configured to provide band pass filtering for previous stage harmonic suppression.

31. The BPSK modulation system as set forth in claim 6, further comprising adjustment means for adjusting carrier suppression, said adjustment means including a fixed transformer and a variable tuning capacitor, said fixed transformer in communication with said first and second induction means.

9. A frequency multiplier circuit, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means having first and second leg outputs, said transformer configured such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second inductor, receiving said "MOD +", said second base in circuit with said second output of said second inductor, receiving said "MOD -".

10. A frequency multiplier circuit, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means having first and second leg outputs, said transformer configured such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second inductor, receiving said "MOD +", said second base in circuit with said second output of said second inductor, receiving said "MOD -".

11. A frequency multiplier circuit utilizing a loosely coupled transformer to adjust carrier suppression, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means loosely coupled with said first induction means, said second induction means having first and second leg output, said transformer configured such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

first and second capacitors, said first capacitor in parallel circuit with said carrier input leg and grounded output leg of said first induction means, said second capacitor in parallel circuit with said first and second leg outputs of said second induction means,

phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second inductor, receiving said "MOD +", said second base in circuit with said second output of said second inductor, receiving said "MOD -".

12. The method of modulating a carrier between a 0 degree phase shift and a 180 degree phase shift, comprising the following steps:

a. providing a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, and second induction means having first and second leg outputs, and a tunable slug or core in communication with said first and second induction means;

b. tuning said slug or core such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

c. providing first and second phase selection means configured to modulate via input of said first and second leg outputs of said second induction means, said first and second phase selection means further comprising first and second load transistors, respectively, each having an emitter, a collector, and a base;

d. configuring said base of said first transistor in circuit with said first output leg of said second inductor, receiving said "MOD +", said base of said second transistor in circuit with said second output leg of said second inductor, receiving said "MOD -".

13. The method of utilizing a loosely coupled transformer to adjust carrier suppression, modulating a carrier signal between a 0 degree phase shift and a 180 degree phase shift, comprising the following steps:

a. providing a transformer, said transformer further comprising an inductor having first induction means having a carrier input leg, an output leg, and windings, and second induction means having first and second leg outputs and windings;

b. coupling said windings of said first and second induction means to a >

0.6 and <

0.3 coupling coefficient;

c. modulating said inductor at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

d. providing first and second phase selection means configured to modulate via input of said first and second leg outputs of said second induction means, said first and second phase selection means further comprising first and second load transistors, respectively, each having an emitter, a collector, and a base;

e. configuring said base of said first transistor in circuit with said first output leg of said second inductor, receiving said "MOD +", said base of said second transistor in circuit with said second output leg of said second inductor, receiving said "MOD -".

14. The method of claim 13, wherein there is included the further step of providing first and second capacitors, said first capacitor in parallel circuit with said carrier input leg and grounded output leg of said first induction means, said second capacitor in parallel circuit with said first and second leg outputs of said second induction means.

15. The method of multiplying a carrier to provide a higher frequency harmonic, comprising the following steps:

a. providing a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, and second induction means having first and second leg outputs, and a tunable slug or core in communication with said first and second induction means;

b. tuning said slug or core such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

c. providing phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second inductor, receiving said "MOD +", said second base in circuit with said second output of said second inductor, receiving said "MOD -",

d. configuring said first base in circuit with said first output leg of said second inductor, receiving said "MOD +", and said second base in circuit with said second output leg of said second inductor, receiving said "MOD -", multiplying the carrier to provide a higher frequency harmonic.

16. The method of utilizing a loosely coupled transformer to adjust carrier suppression, modulating a carrier signal between a 0 degree phase shift and a 180 degree phase shift, and multiplying a carrier to provide a higher frequency harmonic, comprising the following steps:

a. providing a transformer, said transformer further comprising an inductor having first induction means having a carrier input leg, an output leg, and windings, and second induction means having first and second leg outputs and windings;

b. coupling said windings of said first and second induction means to a >

0.6 and <

0.3 coupling coefficient;

c. modulating said inductor at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

d. providing phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second inductor, receiving said "MOD +", said second base in circuit with said second output of said second inductor, receiving said "MOD -".

e. configuring said first base in circuit with said first output leg of said second inductor, receiving said "MOD +", and said second base in circuit with said second output leg of said second inductor, receiving said "MOD -", multiplying the carrier to provide a higher frequency harmonic.

17. The method of claim 16, wherein there is included the further step of providing first and second capacitors, said first capacitor in parallel circuit with said carrier input leg and grounded output leg of said first induction means, said second capacitor in parallel circuit with said first and second leg outputs of said second induction means.

18. A BPSK modulator comprising:

a center tapped transformer having first and second primary legs, said center tapped transformer having a secondary;

amplification means coupled to both first and second primary legs of said center tapped transformer;

selection means, coupled through said amplification means to said center tapped transformer, said selection means driven by a BPSK data input, for enabling one of the first and second primary legs of said center tapped transformer; and

coupling means attached to said secondary of said center tapped transformer to yield BPSK carrier modulation.

19. The BPSK modulator as set forth in claim 18, wherein said center tapped transformer is turned to a resonance frequency by at least one capacitor, thereby providing low cost filtering.

20. The BPSK modulator as set forth in claim 18, wherein said amplification means provides frequency multiplication.

21. A BPSK modulator comprising:

a plurality of logic gates, each logic gate coupled to a primary leg of a transformer, to provide amplification;

selection means, responsive to a BPSK data input, to enable one of said plurality of logic gates; and

coupling means to yield a BPSK modulating carrier signal on a secondary of the transformer.

22. The BPSK modulator as set forth in claim 21 wherein the transformer is tuned to a resonance frequency by a plurality of capacitors, thereby providing low cost filtering.

23. The BPSK modulator as set forth in claim 21 wherein each of said plurality of logic gates provides frequency multiplication.

24. A frequency multiplier circuit, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means having first and second leg outputs, said transformer configured such that said first and second leg outputs of said second induction means modulate at opposite phases of 180 degrees and 0 degrees, forming "MOD +" and "MOD -", respectively, relative to a carrier signal supplied to said carrier input of said first induction means; and

phase selection means configured to modulate via input of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHz, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first leg output of said second induction means, receiving said "MOD +", said second base in circuit with said second leg output of said second induction means, receiving said "MOD -".

25. A frequency multiplier circuit, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means having first and second leg outputs, said transformer configured such that said first and second leg outputs of said second induction means modulate at opposite phases of 180 degrees and 0 degrees, forming "MOD +" and "MOD -", respectively, relative to a carrier signal supplied to said carrier input of said first induction means; and

phase selection means configured to modulate via input of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHz, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second induction means, receiving said "MOD +", said second base in circuit with said second output of said second induction means, receiving said "MOD -".

26. A frequency multiplier circuit utilizing a loosely coupled transformer to adjust carrier suppression, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means loosely coupled with said first induction means, said second induction means having first and second leg outputs, said transformer configured such that said first and second leg outputs of said second induction means modulate at opposite phases of 180 degrees and 0 degrees, forming "MOD +" and "MOD -", respectively, relative to a carrier signal supplied to said carrier input of said first induction means;

first and second capacitors, said first capacitor in parallel circuit with said first and second leg outputs of said second induction means; and

phase selection means configured to modulate via input of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHz, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second induction means, receiving said "MOD +", said second base in circuit with said second output of said second induction means, receiving said "MOD -".

27. The method of multiplying a carrier to provide a higher frequency harmonic, comprising the following steps:

a. providing a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, and second induction means having first and second leg outputs, and a tunable slug or core in communication with said first and second induction means;

b. tuning said slug or core such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

c. providing phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second inductor, receiving said "MOD +", said second base in circuit with said second output of said second inductor, receiving said "MOD -"; and

d. configuring said first base in circuit with said first output leg of said second inductor, receiving said "MOD +", and said second base in circuit with said second output leg of said second inductor, receiving said "MOD -", multiplying the carrier to provide a higher frequency harmonic.

28. The method of utilizing a loosely coupled transformer to adjust carrier suppression, modulating a carrier signal between a 0 degree phase shift and a 180 degree phase shift, and multiplying a carrier to provide a higher frequency harmonic, comprising the following steps:

a. providing a transformer, said transformer further comprising an inductor having first induction means having a carrier input leg, an output leg, and windings, and second induction means having first and second leg outputs and windings;

b. coupling said windings of said first and second induction means to a >

0.6 and <

0.3 coupling coefficient;

c. modulating said inductor at opposite phases of 180 degrees and 0 degrees, forming "MOD +" and "MOD -", respectively, relative to a carrier signal supplied to said carrier input of said first induction means;

d. providing phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second inductor, receiving said "MOD +", said second base in circuit with said second output of said second inductor, receiving said "MOD -".

e. configuring said first base in circuit with said first output leg of said second inductor, receiving said "MOD +", and said second base in circuit with said second output leg of said second inductor, receiving said "MOD -", multiplying the carrier to provide a higher frequency harmonic.

29. A BPSK Modulator circuit having a fixed transformer and a variable tuning capacitor, the fixed transformer and variable tuning capacitor to adjust carrier suppression in a spread spectrum system, comprising:

a transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, second induction means having first and second leg outputs, a fixed transformer, and a variable tuning capacitor, the fixed transformer in communication with said first and second induction means, said transformer configured such that said first and second leg outputs of said second induction means modulate at opposite phases of 180 degrees and 0 degrees, forming "MOD +" and "MOD -", respectively, relative to a carrier signal supplied to said carrier input of said first induction means; and

first and second phase selection means configured to modulate via input of said first and second outputs of said second induction means, said first and second phase selection means further comprising first and second load transistors, respectively, each having an emitter, a collector, and a base, said base of said first transistor in circuit with said first output let of said second induction means, receiving said "MOD +", said base of said second transistor in circuit with said second output of said second induction means, receiving said "MOD -".

32. The method of multiplying a carrier to provide a higher frequency harmonic, comprising the following steps:

a. providing a fixed transformer, said transformer further comprising first induction means having a carrier input leg and an output leg, and second induction means having first and second leg outputs, and a variable tuning capacitor, said fixed transformer in communication with said first and second induction means;

b. tuning fixed transformer and variable tuning capacitor such that said first and second leg outputs of said second induction means modulates at opposite phases of 180 degrees and 0 degrees, forming "MOD +" and "MOD -", respectively, relative a carrier signal supplied to said carrier input of said first induction means;

c. providing phase selection means configured to modulate via input of said of said first and second outputs of said second induction means, said phase selection means having a F_t >

1 GHZ, and further comprising an emitter, and first and second bases or the equivalent, said first base in circuit with said first output of said second induction means, receiving said "MOD +", said second base in circuit with said second output of said second induction means, receiving said "MOD -"; and

d. configuring said first base in circuit with said first output leg of said second induction means, receiving said "MOD +", and said second base in circuit with said second output leg of said second induction means, receiving said "MOD -", multiplying the carrier to provide a higher frequency harmonic.