Sequentially balanced modulation tone ranging system and method

A ranging system, comprising

• a first system for producing a modulation tone ranging signal for transmission, comprising
• means for providing a carrier signal of a first frequency
• means for providing a tone signal of a second frequency
• means for mixing the carrier signal with the tone signal to produce an upper sideband signal at a frequency equal to the sum of the first and second frequencies and to produce a lower sideband signal at a frequency equal to the difference of the first and second frequencies;
• and
• means for separately and sequentially providing the upper and lower sideband signals to produce a sequentially balanced modulation tone ranging signal for transmission;
• and
• a second system for producing a phase shift information signal from a received said sequentially balanced modulation tone ranging signal, comprising
• means for providing a first local signal at a frequency equal to the difference of an intermediate frequency from the first frequency plus or minus the second frequency with the first and second frequencies being alternately added and subtracted in sequential synchronization with the upper and lower sideband signals respectively;
• means for heterodyning the received signal with the first local signal to produce an intermediate frequency received signal;
• means for providing a second local signal at a frequency equal to the sum of the intermediate frequency plus a measurement frequency;
• means for heterodyning the intermediate frequency received signal with the second local signal to produce a received measurement signal;
• means for providing a third local signal at the measurement frequency;
• and
• means for subtracting the phase of the received measurement signal from the phase of the third local signal to produce a phase shift information signal for sequentially indicating the phase shift in the upper and lower sidebands of the received signal.

A system for producing phase shift information signal from a received sequentially balanced modulation tone ranging signal that contains sequentially separated upper and lower sideband signals produced by mixing a carrier signal of a first frequency with a tone signal of a second frequency, wherein the upper sideband signal has a frequency equal to the sum of the first and second frequencies, and the lower sideband signal has a frequency equal to the difference of the first and second frequencies, the system comprising

• means for providing a first local signal at a frequency equal to the difference of an intermediate frequency from the first frequency plus or minus the second frequency with the first and second frequencies being alternately added and subtracted in sequential synchronization with the upper and lower sideband signals respectively;
• means for heterodyning the received signal with the first local signal to produce an intermediate frequency received signal;
• means for providing a second local signal at a frequency equal to the sum of the intermediate frequency plus a measurement frequency;
• means for heterodyning the intermediate frequency received signal with the second local signal to produce a received measurement signal;
• means for providing a third local signal at the measurement frequency;
• and
• means for subtracting the phase of the received measurement signal from the phase of the third local signal to produce a phase shift information signal for sequentially indicating the phase shift in the upper and lower sidebands of the received signal.

A system for producing a phase shift information signal from a received sequentially balanced modulation tone ranging signal that contains sequentially separated upper and lower sideband signals produced by mixing a carrier signal of a first frequency with a tone signal of a second frequency, wherein the upper sideband signal has a frequency equal to the sum of the first and second frequencies, and the lower sideband signal has a frequency equal to the difference of the first and second frequencies, the system comprising

• means for processing the received signal to produce a measurement signal containing the phase information of the received signal at a measurement frequency;
• means for providing a local signal at the measurement frequency;
• and
• means for subtracting the phase of the measurement signal from the phase of the local signal to produce a phase shift information signal for sequentially indicating the phase shift in the upper and lower sidebands of the received signal.

A ranging method, comprising

• a first method for producing a modulation tone ranging signal for transmission comprising the following steps:
• providing a carrier signal of a first frequency;
• providing a tone signal of a second frequency;
• mixing the carrier signal with the tone signal to produce an upper sideband signal at a frequency equal to the sum of the first and second frequencies and to produce a lower sideband signal at a frequency equal to the difference of the upper and lower frequencies;
• and
• separately and sequentially providing the upper and lower sideband signals to produce a sequentially balanced modulation tone ranging signal for transmission;
• and
• a second method for producing a phase shift information signal from a received said sequentially balanced modulation tone ranging signal, comprising the following steps:
• processing the received signal to produce a measurement signal containing the phase information of the received signal at a measurement frequency;
• providing a local signal at the measurement frequency;
• and
• subtracting the phase of the measurement signal from the phase of the local signal to produce a phase shift information signal for sequentially indicating the phase shift in the upper and lower sidebands of the received signal.

A ranging method, comprising

• a first method comprising the following steps:
• providing a carrier signal of a first frequency;
• providing a tone signal of a second frequency;
• mixing the carrier signal with the tone signal to produce an upper sideband signal at a frequency equal to the sum of the first and second frequencies and to produce a lower sideband signal at a frequency equal to the difference of the upper and lower frequencies;
• and
• separately and sequentially providing the upper and lower sideband signals to produce a sequentially balanced modulation tone ranging signal for transmission;
• and
• a second method for producing a phase shift information signal from a received said sequentially balanced modulation tone ranging signal, comprising the following steps:
• providing a first local signal at a frequency equal to the difference of an intermediate frequency from the first frequency plus or minus the second frequency with the first and second frequencies being alternately added and subtracted in sequential synchronization with the upper and lower sideband signals respectively;
• heterodyning the received signal with the first local signal to produce an intermediate frequency received signal;
• providing a second local signal at a frequency equal to the sum of the intermediate frequency plus a measurement frequency;
• heterodyning the intermediate frequency received signal with the second local signal to produce a received measurement signal;
• providing a third local signal at the measurement frequency;
• and
• subtracting the phase of the received measurement signal from the phase of the third local signal to produce a phase shift information signal for sequentially indicating the phase shift in the upper and lower sidebands of the received signal.

A method for producing a phase shift information signal from a received sequentially balanced modulation tone ranging signal that contains sequentially separated upper and lower sideband signals produced by mixing a carrier signal of a first frequency with a tone signal of a second frequency wherein the upper sideband signal has a frequency equal to the sum of the first and second frequencies, and the lower sideband signal has a frequency equal to the difference of the first and second frequencies, the method comprising the following steps:

• providing a first local signal at a frequency equal to the difference of an intermediate frequency from the first frequency plus or minus the second frequency with the first and second frequencies being alternately added and subtracted in sequential synchronization with the upper and lower sideband signals respectively;
• heterodyning the received signal with the first local signal to produce an intermediate frequency received signal;
• providing a second local signal at a frequency equal to the sum of the intermediate frequency plus a measurement frequency;
• heterodyning the intermediate frequency received signal with the second local signal to produce a received measurement signal;
• providing a third local signal at the measurement frequency;
• and
• subtracting the phase of the received measurement signal from the phase of the third local signal to produce a phase shift information signal for sequentially indicating the phase shift in the upper and lower sidebands of the received signal.

A method of producing a phase shift information signal from a received sequentially balanced modulation tone ranging signal that contains sequentially separated upper and lower sideband signals produced by mixing a carrier signal of a first frequency with a tone signal of a second frequency, wherein the upper sideband signal has a frequency equal to the sum of the first and second frequencies, and the lower sideband signal has a frequency equal to the difference of the first and second frequencies, the method comprising the following steps:

• processing the received signal to produce a measurement signal containing the phase information of the received signal at a measurement frequency;
• providing a local signal at the measurement frequency;
• and
• subtracting the phase of the measurement signal from the phase of the local signal to produce a phase shift information signal for sequentially indicating the phase shift in the upper and lower sidebands of the received signal.