Method and apparatus for reducing the peak envelope voltage of an RF transmitter while maintaining signal average power

• US 5,201,071 A
• Filed: 09/26/1990
• Issued: 04/06/1993
• Est. Priority Date: 09/26/1990
• Status: Expired due to Fees

• Current Assignee: Rockwell International Corporation
• Original Assignee: Rockwell International Corporation
• Inventors: Webb, Kenneth F.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Pham, Chi H.
• Application Number:
  US07/589,305
• Time in Patent Office: 923 Days
• Field of Search: 455/48, 455/59, 455/60, 455/101, 455/103, 455/104, 455/105, 455/109, 375/40, 375/38, 375/43, 375/60, 375/61
• US Class Current: 455/101
• CPC Class Codes: H04B 1/68 for wholly or partially suppressing the carrier or one side band
• CPC Class Codes: H04L 1/02 by diversity reception
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26

Abstract

The average RF power output of an independent sideband diversity radio transmitter, modulated by a multiple tone data signal, is increased while the RF output peak envelope voltage is held constant. For diversity operation the same information, as a combination of the data tones, is applied to both the upper and lower sideband channels of the RF translator. Adding predetermined phase shifts between the upper and lower sideband audio tone pairs results in a reduced peak envelope voltage at the composite RF output. The final RF amplifier gain can then be increased resulting in a higher average RF power output.

Claims

1. A diversity radio transmission apparatus capable of increased power output, comprising:

means for providing first and second information carrying baseband signals comprising a multiplicity of components of different frequencies;

means for shifting the phase of the first baseband signal by a predetermined amount coupled to said means for providing baseband signals;

means for generating an RF signal coupled to said phase shifting means having said first and second baseband signals symmetrically disposed around a common frequency;

wherein said RF signal may be transmitted to a receiver via an antenna means; and

wherein said shifting evenly distributes the phase differences between the shifted and unshifted tone pairs over a 360 degree span.

2. A diversity radio transmission apparatus capable of increased power output, comprising:

means for providing first and second information carrying baseband signals comprising a multiplicity of components of different frequencies;

means for shifting the phase of the first baseband signal by a predetermined amount coupled to said means for providing baseband signals;

means for generating an RF signal coupled to said phase shifting means having said first and second baseband signals symmetrically disposed around a common frequency;

wherein said RF signal may be transmitted to a receiver via an antenna means;

wherein said shifting means comprises means for delaying said first portion of said audio signal; and

wherein said delaying means evenly distributes the phase shifts delayed versus undelayed tones over a span of 360 degrees.

3. A diversity radio transmission apparatus capable of increased power output, comprising:

means for providing first and second information carrying baseband signals comprising a multiplicity of components of different frequencies;

means for shifting the phase of the first baseband signal by a predetermined amount coupled to said means for providing baseband signals;

means for generating an RF signal coupled to said phase shifting means having said first and second baseband signals symmetrically disposed around a common frequency;

wherein said RF signal may be transmitted to a receiver via an antenna means; and

wherein said shifting means comprises means for inverting a portion of the tones in said audio tone.

4. A multitone radio transmission apparatus as described in claim 3 wherein said inverting means inverts alternate tones in said audio tone.

5. A multitone diversity radio transmission apparatus capable of increased power output comprising:

means for providing a digital information carrying signal;

means for generating a multiple tone baseband signal each tone of which is representative of the instantaneous digital value of the information carrying signal coupled to said means for providing a digital signal;

means for generating first and second baseband signals related to the multiple tone baseband signal coupled to said means for generating multiple tone baseband signal;

means for shifting the phase of the first generated baseband signal by a predetermined amount coupled to said generating baseband signal means; and

means for generating an RF signal coupled to said phase shifting means having said first and second generated audio signals disposed around a common center frequency;

wherein said shifting means comprises means for delaying said first generated audio signal; and

wherein said delaying means evenly distributes the phase shifts delayed versus undelayed tones over a span of 360 degrees.