Abstract: A smart cellphone application is used as sound pressure level meter for determining if ambient noise infringes the legal limit, and sends evidence to prove the infringement to the law enforcement agency. The application play in the speaker at least one reference burst tone, and use Fast Fourier Transform (FFT) to achieve the mentioned functionality.

Abstract: A smart cellphone application is used as sound pressure level meter for determining if ambient noise infringes the legal limit, and sends evidence to prove the infringement to the law enforcement agency. The application play in the speaker at least one reference burst tone, and use Fast Fourier Transform (FFT) to achieve the mentioned functionality.

Abstract: A network of local area audience response systems is coupled together at a central audience response processing station by a satellite communication system for real time audience response analysis, nationally or internationally. Each local area station and each response unit may be identified and verified by allocation of specific time slots for response preferably synchronously related to a TV picture program transmission carrying the audience questions to be answered. Wireless transmission of the question and answer signals in digital format of beeps of a single frequency keeps transmission channels narrow. The system may be operated in conjunction with TV broadcasting or independently.

Abstract: A network of local area audience response systems is coupled together at a central audience response processing station by means of a satellite communication system for real time audience response analysis, nationally or internationally. Each local area station and each response unit may be identified and verified by allocation of specific time slots for response, preferable synchronously related to a TV picture program transmission carrying the audience questions to be answered. Wireless transmission of the question and answer signals in digital format of beeps of a single frequency keep transmission channels narrow. The system may be operated in conjunction with TV broadcasting or independently.

Abstract: A network of local area audience response systems is coupled together at a central audience response processing station by means of a satellite communication system for real time audience response analysis, nationally or internationally. Each local area station and each response unit may be identified and verified by allocation of specific time slots for response, preferable synchronously related to a TV picture program transmission carrying the audience questions to be answered. Wireless transmission of the question and answer signals in digital format of beeps of a single frequency keep transmission channels narrow. The system may be operated in conjunction with TV broadcasting or independently.

Abstract: In a TV answer back system where many receiver stations communicate with a TV transmitter station by means of rf pulses generated by rf oscillators at the receiver station, the requirement for keeping all oscillators on frequency is achieved without crystal temperature control by automatically controlling the rf oscillator frequency using synchronization signals carried in the video signal received from the TV studio. By this invention it has been possible to control the frequency of multiple megahertz oscillator as accurately as desired from relatively low frequency synchronizing signals such as the vertical and horizontal video sync pulses. Thus an oscillations counter is gated for a very accurate time period by the sync pulses, and the oscillation count is compared with a datum count representing the desired oscillation frequency.

Abstract: Query signals are transmitted by wireless means from the television station to the television set. Response units at receiver locations have a radio frequency transmitter send a response to the station inquiry sent on horizontal lines of the T.V. signal at controlled times identifying each station. This response is a simple r-f beep synchronized with the T.V. signal, in such a way that each set transmitter emits the beep only in its unique time slot. Simplified response units are tuned to the standard intermediate frequency of the T.V. sets and thus need not be wired in and need not have a channel selector.