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| Number | Title | Issue Date |
| 4486898 | Amplitude limiter for AM broadcast transmitter An amplitude limiter for an AM broadcast transmitter to minimize energy in the broadcasted signal outside an allocated broadcast bandwidth. The secondary and higher order spectra (i.e. second and higher harmonics) of a broadcasted AM stereophonic signal a... | 12/04/1984 |
| 4477924 | AM Stereo detector The method and apparatus for providing an AM stereo receiver suitable for receiving an AM/PM modulated RF carrier frequency, the receiver uses a standard AM detector to receive said AM/PM modulated intermediate frequency and to provide an 1+r signal. The ... | 10/16/1984 |
| 4475244 | Time-period modulation transmission system A system for time-period modulating (TPM) a subcarrier in accordance with the amplitude of an input signal includes generating a ramp signal of constant slope, comparing the ramp signal with the input signal, and resetting the ramp signal when the ramp si... | 10/02/1984 |
| 4472831 | AM Stereophonic transmitter An AM stereophonic signal transmitter includes a matrix circuit which generates a sum signal corresponding to the sum of left and right channel stereophonic signals and a difference signal corresponding to the difference between the left and right channel... | 09/18/1984 |
| 4458361 | AM Stereo Broadcasting system An AM stereo broadcasting system for transmitting stereo signals in the AM broadcasting band. The system is based on amplitude modulation by two carriers having the same frequency and a 90° phase difference from each other, and is capable of increasing t... | 07/03/1984 |
| 4451927 | Separation correction method and apparatus for plural channel transmission system Apparatus is disclosed for use in improving the separation between the individual channels of a plural channel communication system such as a stereo AM radio broadcasting system. The separation corrections are made to the baseband signals. Two sources (14... | 05/29/1984 |
| 4373115 | Predictive distortion reduction in AM stereo transmitters An apparatus for generating a composite AM stereo broadcast signal wherein a carrier is angle modulated with stereo difference information contained in a first supplied signal and the angle-modulated carrier is then amplitude modulated with stereo sum inf... | 02/08/1983 |
| 4338491 | Compatible AM stereophonic system The signal as transmitted is a compatible AM stereophonic signal with amplitude directly proportional to the monophonic signal 1+L+R. The instantaneous phase angle is the quadrature phase angle modified in that high level, high frequencies in the L-R chan... | 07/06/1982 |
| 4332978 | Low frequency AM stereophonic broadcast and receiving apparatus Apparatus is described for transmitting and receiving stereophonic broadcasts in the low frequency commercial AM broadcast band. A transmitter is described which modulates the phase and amplitude of a broadcast signal with separate information signals. A ... | 06/01/1982 |
| 4324952 | Direct function receivers and transmitters for multichannel communications system Transmitters and receivers are disclosed for communicating composite modulated signals including at least two modulated components. The transmitters include phase and envelope operators (54, 56) which generate the phase and envelope portions of the compos... | 04/13/1982 |
| 4323731 | Variable-angle, multiple channel amplitude modulation system A compatible AM stereo system employing a modified quadrature modulation scheme where the gain in the quadrature-phased channel, and thus the phase angle between the L and R modulated phase components of the composite modulated signal, is dynamically vari... | 04/06/1982 |
| 4236042 | Compatible AM stereo system employing a modified quadrature modulation scheme A compatible AM stereo system including a modified quadrature modulation scheme. Two stereo modulators are described which each generate composite modulated signals including a carrier component and two phase-shifted components. The two phase-shifted comp... | 11/25/1980 |
| 4225751 | Variable-angle, multiple channel amplitude modulation system A compatible AM stereo system employing a modified quadrature modulation scheme where the gain in the quadrature-phased channel, and thus the phase angle between the L and R modulated phase components of the composite modulated signal, is dynamically vari... | 09/30/1980 |
| 4220818 | AM Stereo transmitter A transmitter for an independent sideband (ISB) AM stereo system is provided with a phase modulator which includes means for generating second order upper and lower sidebands which are proportional to the stereo difference signal. No second order upper an... | 09/02/1980 |
| 4218586 | Compatible AM stereo broadcast system A compatible AM stereo broadcasting system is disclosed in which the signal is a carrier having an amplitude directly variable with monoaural or sum (L+R) information, and having an instantaneous phase $c; varying as a function of the resultant amplitu... | 08/19/1980 |
| 4194088 | Modulation monitor for AM stereophonic broadcasts Apparatus is described for removing stereophonic signals contained in a broadcast signal. Removal of a stereophonic indicator tone frequency on the broadcast signal is also provided. Separate outputs measuring both a summation signal of left plus right au... | 03/18/1980 |
| 4194154 | Narrow bandwidth network compensation method and apparatus A method and means for compensating for the limited bandwidth of antennas and antenna coupling networks and other high powered modulated wave equipment characterized by generating a modulated wave at a relatively low power level, passing the modulated wav... | 03/18/1980 |
| 4185171 | Compatible single sideband system for AM stereo broadcasting A system for the transmission and reception of two program signals L and R on a single channel by means of a compatible SSB AM stereophonic signal having the form (1+L+R)cos(ωc t+$c;) where $c; is arc sin{[(L-R)/π/2] [1+(L +R)/2] / (1+L... | 01/22/1980 |
| 4184046 | Compatible single sideband system for AM stereo A CSSB system for AM stereo provides both second and third order sideband correction in the transmitted signal for reduction of distortion at the receivers. Sum and difference signals are derived from two audio program signals (L and R) and shifted in pha... | 01/15/1980 |
| 4182932 | A-m stereo system Means and method for generation and combination at a transmitting apparatus and separation and demodulation at a receiving apparatus of two signals comprising carrier waves of the same frequency but having different phase, modulated with different program... | 01/08/1980 |
| 4159398 | Stereo presence signal for an AM stereo system In an AM broadcast transmitter, an infrasonic tone is added to the difference channel of a compatible AM stereo system to provide a stereo presence signal. In a stereophonic receiver, the corrected output of a synchronous detector in the difference signal... | 06/26/1979 |
| 4124779 | Dual channel communications system particularly adapted for the AM broadcast band A communication system is adapted to particularly operate in the AM (amplitude modulated) broadcast band and accommodates stereo transmission via a left and a right channel. The system includes a transmitter which provides an upper and lower sideband; eac... | 11/07/1978 |
| 4105868 | AM stereophonic transmission system An AM sterophonic broadcast signal for transmitting stereophonically related first and second audio information signals to at least one receiver comprises a first carrier component, a double-sideband component of a second carrier component being suppresse... | 08/08/1978 |
| 4079204 | AM Stereophonic transmission system An AM stereophonic transmission system in which a carrier wave signal is phase- or frequency-modulated by an audio composite signal L - jR or L + jR and the phase- or frequency-modulated carrier wave signal is further amplitude-modulated by an audio compo... | 03/14/1978 |
| 4068100 | Method and apparatus for transmitting and receiving amplitude modulated stereo The transmission of amplitude modulated stereo is achieved by modulating the positive and negative half cycles of a radio frequency carrier separately with a different one of the channels carrying the audio intelligence of a stereo program, thereby transm... | 01/10/1978 |
