F-modulation amplification

• US 5,491,457 A
• Filed: 01/09/1995
• Issued: 02/13/1996
• Est. Priority Date: 01/09/1995
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Kamilo Feher
• Inventors: Feher, Kamilo
• Primary Examiner(s): MIS, DAVID C
• Application Number:
  US08/370,117
• Time in Patent Office: 400 Days
• Field of Search: 332/100, 332/101, 332/102, 332/103-105, 375/261, 375/271-284, 375/298, 375/302-308
• US Class Current: 332/103
• CPC Class Codes: H03C 3/005 Circuits for asymmetric modulation
• CPC Class Codes: H04L 27/2032 for discrete phase modulation, e.g. in which the phase of the carrier is modulated in a nominally instantaneous manner
• CPC Class Codes: H04L 27/362 Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated H04L27/366 takes precedence
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits

Abstract

Binary and Quadrature Feher'"'"'s (F)-Modulation/Amplification with significantly reduced envelope fluctuations and peak radiation, increased power efficiency and transmit power delivered by connected RF (radio frequency), Infrared (IR) and other devices. A subclass of these systems has a constant envelope. Extraordinary power advantages, robust BER performance and linearly or nonlinearly amplified narrow spectrum without the pitfalls of conventional BPSK and DBPSK is attained. The FBPSK improved efficiency transmitter is compatible with conventional BPSK receivers. FBPSK modems are based on using quadrature structure where Q channel data is inserted in quadrature with I channel data. The Q channel data is the same as the I channel but is offset by one half bit (Tb/2). Further improvement in the spectrum is attained using correlation between I and Q channels. FBPSK modem is shown to meet the IEEE 802.11 specified spectral mask (-30 dB point) for wireless LAN, and leads output power gain of 6.5 dB over BPSK modems. The Crosscoupled Quadrature Structure is also suitable for digital and for analog frequency modulation (Feher'"'"'s Frequency Modulation). Reduced modulation index Gaussian FSK (GFSK), multilevel FM and crosscoupled Quadrature Amplitude Modulated (QAM) transmitters and combinations of these modulations and corresponding coherent demodulators are described.

Claims

1. A structure comprising:

a input port for receiving input data;

a splitter having an input coupled to said input port, and serving to split said input data into baseband signal streams; and

a baseband signal processing network for receiving said baseband signal streams and providing cross-correlated processed in phase and quadrature phase baseband signals.

2. A structure as in claim 1 which further comprises a quadrature modulator for receiving said processed in phase and quadrature phase baseband signals and providing a quadrature modulated output signal.

3. A structure as in claim 1 wherein said baseband processing network comprises for each of an I and Q channel:

an input port for receiving one of said baseband signal streams from said splitter;

a delay element coupled to said input port for delaying said one of said baseband signal streams a predefined period of time greater than or equal to zero and producing a delayed baseband signal;

an amplifier coupled to receive said delayed baseband signal and adjust its gain to provide a gain adjusted baseband data signal; and

a filter coupled to receive said gain adjusted baseband data signal and provide a filtered baseband data signal for output to a quadrature modulator.

4. The structure as in claim 3 wherein said baseband processing network further comprises a cross-coupler for receiving said filtered baseband data signal and providing in response thereto a cross-correlated data output signal for each of said I and Q channels.

5. The structure as in claim 1 wherein said input data comprises an input signal selected from the group consisting of binary, multilevel filtered, multilevel unfiltered and analog signals.

6. The structure as in claim 3 wherein said delay provided in said one of said I and Q channels is greater than the delay provided in the other of said I and Q channels.

7. The structure as in claim 3 wherein said delay provided in said one of said I and Q channels is half a bit period greater than the delay provided in the other of said I and Q channels.

8. The structure as in claim 1 wherein said processed in phase and quadrature phase baseband signals have amplitudes such that their vector sum is substantially constant and has reduced resultant quadrature modulated envelope fluctuations.

9. The structure as in claim 1 which further comprises means for selectively reducing the cross-correlating factor down to zero.

10. The structure as in claim 2 which further comprises an amplifier operated in linear mode for amplifying said quadrature modulated signal and providing a linearly amplified output signal that is band limited.

11. A cross correlated quadrature architecture signal processor for producing cross correlated in phase and quadrature phase signal streams for modulation by a Quadrature Modulator comprising:

a filter for receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and producing a filtered input signal;

signal shaping means for integrating said filtered input signal;

,

an amplifier for varying the modulation index of said signal processor, said amplifier receiving said filtered input signal and providing an amplified input signal;

a splitter receiving said amplified input signal and providing cross correlated data streams; and

a signal processor having an in phase and quadrature phase channel each receiving one of said cross correlated data streams, each of said in phase and quadrature phase channel having a first delay gain filter, means for generating Cosine and Sine values for said in phase and quadrature phase channel datastream, a wave shaper and a second delay gain filter, such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal adaptable for coherent demodulation of the quadrature frequency modulated (FM) signal.

12. A cross correlated quadrature architecture signal processor for producing cross correlated in phase and quadrature phase data streams for modulation by a Quadrature Modulator and subsequent coherent quadrature demodulation of the quadrature FM modulated signal comprising:

a splitter for receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and providing a pair of identical data signals; and

a signal processor including an in phase and quadrature phase channel each receiving one of said pair of identical data signals, each of said channels including

a delay element for receiving said one of said pair of identical data signals and producing a delayed signal;

an amplifier for receiving said delayed signal and producing an amplified data signal;

a filter for receiving said amplified signal and producing a filtered data signal; and

a function generator for generating Cosine and Sine values for said filtered data signal;

such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal adaptable for coherent demodulation of the quadrature FM signal.

13. A cross correlated quadrature architecture signal processor for producing cross correlated in phase and quadrature phase data streams for modulation by a Quadrature Modulator and subsequent demodulation of the quadrature modulated signal comprising:

a splitter for receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and providing a pair of identical signals; and

a signal processor including an in phase and quadrature phase channel each receiving one of said pair of identical signals, each of said channels including

a delay element for receiving said one of said pair of identical signals and producing a delayed signal;

an amplifier for receiving said delayed signal and producing an amplified signal;

a filter for receiving said amplified signal and producing a filtered signal;

such that said signal processor provides in phase and quadrature phase cross correlated signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode adaptable for coherent and noncoherent demodulation.

14. A cross correlated quadrature architecture signal processor for producing cross correlated in phase and quadrature phase data streams for modulation by a Quadrature Modulator and subsequent conventional BPSK or QPSK demodulation of the quadrature modulated signal comprising:

a splitter for receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and providing a pair of identical data signals; and

a signal processor including an in phase and quadrature phase channel each receiving one of said pair of identical data signals, each of said channels including

a delay element for receiving said one of said pair of identical data signals and producing a delayed signal;

an amplifier for receiving said delayed signal and producing an amplified data signal;

a filter for receiving said amplified signal and producing a filtered data signal;

such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode and adaptable for conventional BPSK or QPSK demodulation.

15. A method of cross correlating an input data signal for use in a quadrature architecture modulator for producing cross correlated in phase and quadrature phase data streams for modulation by a Quadrature Modulator and subsequent conventional BPSK demodulation of the quadrature modulated signal comprising the steps of:

splitting an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and providing a pair of identical data signals;

delaying each of said pair of identical data signals and producing a pair of delayed signals;

amplifying each of said pair of delayed signals and producing a pair of amplified data signals; and

filtering each of said pair of said amplified signals and producing a filtered data signal;

such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation characterized by a modulated signal suitable for amplification in linear and non-linear mode and adaptable for conventional BPSK demodulation.

16. A quadrature architecture spectral and power efficient modem comprising:

a splitter for receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and providing a pair of identical data signals;

a signal processor including an in phase and quadrature phase channel each receiving one of said pair of identical data signals, each of said channels including

a delay element for receiving said one of said pair of identical data signals and producing a delayed signal;

an amplifier for receiving said delayed signal and producing an amplified data signal;

a filter for receiving said amplified signal and producing a filtered data signal;

a quadrature modulator for receiving said filtered signals from each of said channels and producing a modulated output signal; and

amplification means operated in non-linear mode for maximum power efficiency receiving said modulated output signal and for transmitting a band limited output signal with substantially limited spectral regrowth.

17. A quadrature architecture modem with out of band spectral density attenuated at least 30 dB at 11 MHz away from the carrier frequency for an 11M-chip/sec system comprising:

a splitter for receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and providing a pair of identical data signals;

a signal processor including an in phase and quadrature phase channel each receiving one of said pair of identical data signals, each of said channels including

a delay element for receiving said one of said pair of identical baseband data signals and producing a delayed signal;

an amplifier for receiving said delayed signal and producing an amplified data signal;

a filter for receiving said amplified signal and producing a filtered data signal;

a quadrature modulator for receiving said filtered signals from each of said channels and producing a modulated output signal; and

amplification means operated in non-linear mode for receiving said modulated output signal and for transmitting a band limited output signal with spectral regrowth limited to a 30 dB spectral density attenuation.

18. A quadrature architecture modem comprising:

a splitter for receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and providing a pair of identical data signals;

a signal processor including an in phase and quadrature phase channel each receiving one of said pair of identical data signals, each of said channels including

a delay element for receiving said one of said pair of identical data signals and producing a delayed signal;

an amplifier for receiving said delayed signal and producing an amplified data signal;

a filter for receiving said amplified signal and producing a filtered data signal;

a quadrature modulator for receiving said filtered signals from each of said channels and producing a modulated output signal; and

amplification means operated in a non-linear saturation amplification mode for maximum power efficiency receiving said modulated output signal and for transmitting a band limited output signal with out-of-band spectral density attenuated at least 30 dB at N Mhz away from the carrier frequency for N Megachip/sec and N megabit/sec systems.

19. The structure as in claim 18 wherein N is an integer selected from the group consisting of 1, 2, 4, 10, 11 and 22.

20. A cross correlated quadrature architecture signal processor for producing cross correlated in phase and quadrature phase data streams for modulation by a Quadrature Modulator and subsequent demodulation of the quadrature modulated signal in digital, binary, multi-level or analog FM systems comprising:

a variable gain element for reducing the modulation index of said quadrature modulator, said variable gain element receiving an input signal selected from the group of binary, multi-level, and analog signals and combinations thereof and outputting an attenuated input signal;

a splitter for receiving said attenuated input signal and providing a pair of identical data signals; and

a signal processor including an in phase and quadrature phase channel each receiving one of said pair of identical data signals, each of said channels including

a delay element for receiving said one of said pair of identical data signals and producing a delayed signal;

a function generator for generating Cosine and Sine values for said delayed signal and producing a shaped signal;

an amplifier for receiving said shaped signal and producing an amplified data signal;

a filter for receiving said amplified signal and producing a filtered data signal;

such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode.

21. A binary phase shift keyed quadrature cross coupled structure suitable for linear and non-linear amplified system applications comprising:

a input port for receiving input data;

a splitter having an input coupled to said input port, and serving to split said input data into in phase (I) and quadrature phase (Q) channel cross coupled datastreams such that said I and Q datastreams are identical, proportional in gain and phase to said input data; and

a signal processing network for receiving said I and Q channel datastreams and providing cross-correlated processed in phase and quadrature phase signals, said signal processing network including

a delay element for delaying one of said I and Q channel datastreams by a selectable time delay;

amplifiers in the I and Q channel for providing gain adjusted datastreams; and

filtering means for filtering said gain adjusted datastreams in the I and Q channels such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode. .

22. A structure as in claim 21 which further comprises a quadrature modulator for receiving said processed in phase and quadrature phase cross correlated data signals and providing a quadrature modulated output signal.

23. A structure as in claim 21 which further comprises switching means for disconnecting one of said in phase and quadrature phase cross correlated data signals allowing for conventional BPSK, QPSK and offset QPSK modulation.

24. A structure as in claim 21 in which said selectable time delay is one half of a chip duration for a spread spectrum system and one half of a bit duration for a non-spread spectrum system.

25. A Gaussian Filtered Frequency Shift Keyed (GFSK) quadrature cross coupled structure suitable for linear and non-linear amplified system applications comprising:

a input port for receiving input data;

a Gaussian lowpass filter and presetable gain integrator for processing said input data and providing filtered input data;

a splitter having an input coupled to said input port, and serving to split said filtered input data into in phase (I) and quadrature phase (Q) channel cross coupled datastreams such that said I and Q datastreams are identical, proportional in gain and phase to said input data; and

a signal processing network for receiving said I and Q channel datastreams and providing processed in phase and quadrature phase signals, said signal processing network including

a signal processor for varying the modulation index for said signal processing network;

means for generating Cosine and Sine values for said I and Q channel datastreams;

a delay element for delaying one of said I and Q channel datastreams by a selectable time delay;

amplifiers in the I and Q channel for providing gain adjusted datastreams; and

filtering means for filtering said gain adjusted datastreams in the I and Q channels such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode. .

26. The structure as in claim 25 wherein said signal processor is selected from the group consisting of a filter, an integrator, and a signal level and gain adjustor.

27. A frequency modulation pre-processor for multistate digital signals suitable for linear and non-linear amplified system applications comprising:

a input port for receiving input data;

a converter for converting said input data into a multilevel N level datastream where N is an integer greater than 1;

a splitter having an input coupled to said input port, and serving to split said multilevel N level datastream into in phase (I) and quadrature phase (Q) channel cross coupled datastreams such that said I and Q datastreams are identical, proportional in gain and phase to said multilevel N level datastream; and

a signal processing network for receiving said I and Q channel datastreams and providing cross-correlated processed in phase and quadrature phase signals, said signal processing network including

a signal processor for varying the modulation index for said signal processing network;

means for generating Cosine and Sine values for said I and Q channel;

a delay element for delaying one of said I and Q channel datastreams by a selectable time delay;

amplifiers in the I and Q channel for providing gain adjusted datastreams; and

filtering means for filtering said gain adjusted datastreams in the I and Q channels such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode.

28. A frequency modulation pre-processor for digital signals suitable for linear and non-linear amplified system applications comprising:

a input port for receiving digital input data;

a converter for converting said digital input data converting said digital input signal into a predetermined coded, filtered and processed signal;

a splitter having an input coupled to said input port, and serving to split said input data into in phase (I) and quadrature phase (Q) channel cross-correlated datastreams such that said I and Q datastreams are identical, proportional in gain and phase to said input data; and

a signal processing network for receiving said I and Q channel datastreams and providing processed in phase and quadrature phase signals, said signal processing network including

a signal processor for presetting the modulation index for said signal processing network;

means for generating Cosine and Sine values for said I and Q channel datastreams;

a delay element for delaying one of said I and Q channel datastreams by a selectable time delay;

amplifiers in the I and Q channel for providing gain adjusted datastreams; and

filtering means for filtering said gain adjusted datastreams in the I and Q channels such that said signal processor provides in phase and quadrature phase cross correlated data signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode.

29. The structure as in claim 28 wherein said signal processor is selected from the group consisting of a filter, an integrator, a delay element, a Cosine and Sine value generator and an amplifier and combinations thereof.

30. A frequency modulation pre-processor for analog signals suitable for linear and non-linear amplified system applications comprising:

a input port for receiving analog input signal;

a splitter having an input coupled to said input port, and serving to split said input signal into in phase (I) and quadrature phase (Q) channel cross coupled signal streams such that said I and Q signal streams are identical, proportional in gain and phase to said input signal; and

a signal processing network for receiving said I and Q channel signal streams and providing cross-correlated processed in phase and quadrature phase signals, said signal processing network including

a delay element for delaying one of said I and Q channel signal streams by a selectable time delay;

amplifiers in the I and Q channel for providing gain adjusted signal streams; and

filtering means for filtering said gain adjusted signal streams in the I and Q channels such that said signal processor provides in phase and quadrature phase cross correlated signals for quadrature modulation with a modulated signal suitable for amplification in linear and non-linear mode.