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US 4,051,438 AGranted
Co-channel multiple signal broadcasting system
AssigneeInternational Telephone and Telegraph Corporation
InventorsRobert B. Pickett, Elie J. Baghdady
Life of this patent
Estimating the term…
Abstract
Interference in the overlapping of at least two transmission transmitters areas of a co-channel multiple signal broadcasting system is suppressed by an asymmetrical radio frequency carrier deviation in one given direction of one of the two transmitters and an asymmetrical radio frequency carrier deviation in a direction opposite to the one given direction of the other of the two transmitters. The oppositely directed asymmetrical carrier deviations create a .+-. 2.5 kHz rms carrier frequency offset from the nominal carrier frequency in a manner which is compatible with present FCC regulations.
Claims5
A co-channel multiple signal broadcasting system to suppress co-channel interference in overlapping areas of transmission signals comprising:
- at least two angularly modulated transmitters disposed in spaced relation with respect to each other such that their respective transmission signals have at least one overlapping area, each of said two transmitters transmitting identical speech bursts by angularly modulating a carrier signal having a given carrier frequency;
- first means disposed in one of said two transmitters to deviate its associated carrier frequency in primarily a first given direction;
- and
- second means disposed in the other of said two transmitters to deviate its associated carrier frequency in primarily a second given direction opposite said first given direction;
- the opposite deviations of said carrier frequencies of said two transmitters providing an effective root mean square separation of said carrier frequencies of said two transmitters to suppress said co-channel interference;
- said first means including
- a first source of said identical speech bursts,
- a first pre-emphasis network coupled to said first source,
- a base clipper coupled to said first pre-emphasis network, and
- a first de-emphasis network coupled to said base clipper;
- and
- said second means including
- a second source of said identical speech bursts,
- a second pre-emphasis network coupled to said second source,
- a peak clipper coupled to said second pre-emphasis network, and
- a second de-emphasis network coupled to said peak clipper.
13 more elements
A co-channel multiple signal broadcasting system to suppress co-channel interference in overlapping areas of transmission signals comprising:
- at least two angularly modulated transmitters disposed in spaced relation with respect to each other such that their respective transmission signals have at least one overlapping area, each of said two transmitters transmitting identical speech bursts by angularly modulating a carrier signal having a given carrier frequency;
- first means disposed in one of said two transmitters to deviate its associated carrier frequency in primarily a first given direction;
- and
- second means disposed in the other of said two transmitters to deviate its associated carrier frequency in primarily a second given direction opposite said first given direction;
- the opposite deviations of said carrier frequencies of said two transmitters providing an effective root means square separation of said carrier frequencies of said two transmitters to suppress said co-channel interference;
- said first means including
- a source of said identical speech bursts,
- a pre-emphasis network coupled to said source,
- a clipper coupled to said pre-emphasis network to clip one of the peaks of said identical speech bursts, and
- a de-emphasis network coupled to said clipper.
7 more elements
A co-channel multiple signal broadcasting system to suppress co-channel interference in overlapping areas of transmission signals comprising:
- at least two angularly modulated transmitters disposed in spaced relation with respect to each other such that their respective transmission signals have at least one overlapping area, each of said two transmitters transmitting identical speech bursts by angularly modulating a carrier signal having a given carrier frequency;
- first means disposed in one of said two transmitters to deviate its associated carrier frequency in primarily a first given direction;
- and
- second means disposed in the other of said two transmitters to deviate its associated carrier frequency in primarily a second given direction opposite said first given direction;
- the opposite deviations of said carrier frequencies of said two transmitters providing an effective root means square separation of said carrier frequencies of said two transmitters to suppress said co-channel interference;
- said second means including
- a source of said identical speech bursts,
- a pre-emphasis network coupled to said source,
- a clipper coupled to said pre-emphasis network to clip one of the peaks of said identical speech bursts, and
- a de-emphasis network coupled to said clipper.
7 more elements
A co-channel multiple signal broadcasting system to suppress co-channel interference in overlapping areas of transmission signals comprising:
- at least two angularly modulated transmitters disposed in spaced relation with respect to each other such that their respective transmission signals have at least one overlapping area, each of said two transmitters transmitting identical speech bursts by angularly modulating a carrier signal having a given carrier frequency;
- first means disposed in one of said two transmitters to deviate its associated carrier frequency in primarily a first given direction;
- and
- second means disposed in the other of said two transmitters to deviate its associated carrier frequency in primarily a second given direction opposite said first given direction;
- the opposite deviations of said carrier frequencies of said two transmitters providing an effective root mean square separation of said carrier frequencies of said two transmitters to suppress said co-channel interference;
- said first means including
- a first source of said identical speech bursts,
- a first reference potential,
- a first capacitor having one terminal thereof coupled to said first source,
- a first resistor coupled in parallel to said first capacitor from said one terminal of said first capacitor to the other terminal of said first capacitor,
- a second resistor coupled from said other terminal of said first capacitor to said first reference potential,
- a first AC coupled isolation amplifier having an output and an input coupled to said other terminal of said first capacitor,
- a third resistor having one terminal thereof coupled to said output of said first AC coupled amplifier,
- a first diode coupled between said first reference potential and the other terminal of said third resistor, said first diode being poled to clip the negative peaks of said identical speech bursts,
- a first DC coupled isolation amplifier having an output and an input coupled to said other terminal of said third resistor,
- a fourth resistor having one of its terminals coupled to said output of said first DC coupled amplifier, and
- a second capacitor coupled between said first reference potential and the other terminal of said fourth resistor, said other terminal of said fourth resistor being the output terminal of said first means;
- and
- said second means including
- a second source of said identical speech bursts,
- a second reference potential,
- a third capacitor having one terminal thereof coupled to said second source,
- a fifth resistor coupled in parallel to said third capacitor from said one terminal of said third capacitor to the other terminal of said third capacitor,
- a sixth resistor coupled from said other terminal of said third capacitor to said second reference potential,
- a second AC coupled isolation amplifier having an output and an input coupled to said other terminal of said third capacitor,
- a seventh resistor having one terminal thereof coupled to said output of said second AC coupled amplifier,
- a second diode coupled between said second reference potential and the other terminal of said seventh resistor, said second diode being poled to clip the positive peaks of said identical speech bursts,
- a second DC coupled isolation amplifier having an output and an input coupled to said other terminal of said seventh resistor,
- an eighth resistor having one of its terminals coupled to said output of said second DC coupled amplifier, and
- a fourth capacitor coupled between said second reference potential and the other terminal of said eighth resistor, said other terminal of said eighth resistor being the output terminal of said second means.
27 more elements
A co-channel multiple signal broadcasting system to suppress co-channel interference in overlapping areas of transmission signals comprising:
- at least two angularly modulated transmitters disposed in spaced relation with respect to each other such that their respective transmission signals have at least one overlapping area, each of said two transmitters transmitting identical speech bursts by angularly modulating a carrier signal having a given carrier frequency;
- first means disposed in one of said two transmitters to deviate its associated carrier frequency in primarily a first given direction;
- and
- second means disposed in the other of said two transmitters to deviate its associated carrier frequency in primarily a second given direction opposite said first given direction;
- the opposite deviations of said carrier frequencies of said two transmitters providing an effective root means square separation of said carrier frequencies of said two transmitters to suppress said co-channel interference;
- said first means including
- a source of said identical speech bursts,
- a reference potential,
- a first capacitor having one terminal thereof coupled to said source,
- a first resistor coupled in parallel to said first capacitor from said one terminal of said first capacitor to the other terminal of said first capacitor,
- a second resistor coupled from said other terminal of said first capacitor to said reference potential,
- an AC coupled isolation amplifier having an output and an input coupled to said other terminal of said first capacitor,
- a third resistor having one terminal thereof coupled to said output of said AC coupled amplifier,
- a diode coupled between said reference potential and the other terminal of said third resistor, said diode being poled to clip the negative peaks of said identical speech bursts,
- a DC coupled isolation amplifier having an output and an input coupled to said other terminal of said third resistor,
- a fourth resistor having one of its terminals coupled to said output of said DC coupled amplifier, and
- a second capacitor coupled between said reference potential and the other terminal of said fourth resistor, said other terminal of said fourth resistor being the output terminal of said first means.
14 more elements
Dependencies are inferred from the claim text.