Leonard T Kahn, 61655 Starboard Dr, Naples, FL 34103

6909381, Jun 21, 2005

Feb 21, 2001

09/790103

Leonard Richard Kahn - New York NY, US

G08B021/00

340945, 340961, 340988, 340980, 702150, 348 61, 348 82, 348143, 348144, 348 39, 345 7, 359400, 359399, 359630

An aircraft collision avoidance system utilizing video signals of the air space surrounding the aircraft for determining whether an object, such as another aircraft, is too close. Use is made of various types of monitors to display the on coming object and its location relative to the protected aircraft. An audio alarm is provided for alerting the pilot of the danger as well as providing localization information. Video recordings store information for accident and near miss studies. The video signals can also be used for the entertainment of airline passengers. One preferred embodiment of the invention permits ground based experts to point out interesting objects that are visible due to the improved view provided passengers.

4217661, Aug 12, 1980

Oct 14, 1975

5/621669

Leonard R. Kahn - New York NY

H04B 168

455 59

An improved system and method for processing relatively high fidelity audio signals having a frequency range, for example, of between about 50 Hz and 5,000 Hz for transmission over two or more relatively low fidelity transmission channels, such as voice grade telephone or radio channels having a limited frequency response of 300 to 3,000 Hz, for example. Typical practice of the invention involves separation of the signal into two halves; one covering the lower segment between about 50 to 2,600 Hz, for example, which is transmitted over one voice grade channel, and the upper segment between about 2,500 Hz to 5,000 Hz, for example, which is transmitted over the second voice grade channel. Two sinusoidal tones are transmitted for frequency and phase correction purposes. The frequencies of these tones are preferably outside the translation frequency range of the signal components and are related in frequency by a simple ratio, typically an integer.

4850020, Jul 18, 1989

Nov 5, 1987

7/117594

Leonard R. Kahn - New York NY

H04H 500

381 16

Asymmetrical sideband amplitude modulation (AM) stereo transmission apparatus which transmits left (L) plus right (R) stereo information (L+R) in one stereo channel and a signal including L-R stereo information in a second stereo channel. Benefits include significant reduction of modulation envelope distortion in null regions of the transmitter's antenna radiation pattern and improved quality of reception in the presence of adjacent channel and co-channel interference, easing of the difficulty in tuning continuously tuned receivers and improvement of the fidelity of such receivers when side tuned, while at the same time providing a signal which, when received and decoded by an independent sideband AM stereo receiver, provides pleasing stereo effects.

5625893, Apr 29, 1997

Jul 26, 1993

8/098560

Leonard R. Kahn - New York NY

H04B 700

455 70

A satellite communications system with improved intermodulation distortion characteristics as the result of incorporating distortion reduction circuitry in the down-link receiver but which is controlled by the up-link transmission equipment.

4143325, Mar 6, 1979

Aug 20, 1976

5/716332

Leonard R. Kahn - New York NY

H04B 110

325478

A squelch circuit for muting constant amplitude interference when the signal is absent. The input wave's envelope characteristic is examined so as to determine if the envelope is constant and, if it is, a gate is controlled so that the input wave is muted. Time delay circuitry is provided in one embodiment in order to provide sufficient time to make a determination that constant amplitude interference is present rather than variable amplitude speech before muting the input wave.

4479153, Oct 23, 1984

May 9, 1979

6/030026

Leonard R. Kahn - New York NY

H04B 110

360 53

A system and method for squelching noise and storing messages. Many receiving systems produce noise bursts at the end of the reception of a message and prior to the operation of the muting circuit. Such noise bursts are especially severe in frequency modulation systems using limiters. By delaying the audio signal until the squelch circuit's hang time is completed the noise bursts are muted. One application of this invention is in vehicles such as police cars and taxicabs. For such an application one of the essential parts of almost every message is the street address where the vehicle is needed. Since it is easy to confuse addresses, and thereby require a repeat of the message, a recording of at least the address portion of the message would be most useful. A storage system is provided in order to allow the repetition of messages.

4811422, Mar 7, 1989

Dec 22, 1986

6/944360

Leonard R. Kahn - New York NY

H04B 104

455114

Reduction of undesired r. f. harmonics, generated in the highest power power amplifier of a transmitter, is achieved by providing at least one alternate path for the undesired harmonics incorporating a relatively low powered power amplifier for at least one undesired harmonic component and causing the harmonic, in this alternate path, to have an amplitude that is substantially equal and a phase 180 degrees relative to the corresponding harmonic output from the main path and combining the outputs of the paths.

4192970, Mar 11, 1980

Apr 18, 1978

5/897305

Leonard R. Kahn - New York NY

H04H 500

179 1GS

An improved system and method for reducing adjacent channel interference radio systems by making use of the so called "cocktail party effect". Also, the selectivity is improved by measuring the level of adjacent channel interference above and below the desired channel and automatically changing selectivity characteristics of the receiver in accordance with the measured interference. The system is particularly applicable to the reception of AM Stereo signals but it may also be used to improve the performance of monophonic systems.