Abstract: A laser satellite communication system which avoids atmospheric, wind and turbulence effects. A satellite or high altitude platform communication system includes an earth-orbiting satellite or high altitude platform carrying a laser communications receiver and an acknowledgement transmitter. A ground terminal having a laser communications transmitter which is caused to continuously transmit large data block signals. When one block of data signals is received at the satellite or platform, an acknowledgement signal is sent to earth from the satellite or platform. The ground terminal receives the acknowledgement signal and causes the ground terminal laser communication transmitter to continuously transmit the next succeeding large block data signals. This process is repeated until all of the data has been received by the earth-orbiting satellite or high altitude platform, whereby all of the large data block signals are received by the laser communication receiver through scintillation windows in the atmosphere.

Abstract: The system and method of the present invention include a modulator which encodes data on a communication signal using angle modulation. The demodulator, receiving the angle modulated communication signal, angle demodulates the angle modulated communication signal to obtain the data. In this manner, separate frequency bands are not required to transmit both the communication signal and the data. The bandwidth of the transmission from the modulator is reduced to the frequency band of the angle modulated communication signal. Additionally, since angle modulations of an audio signal are inaudible to a listener, when the communication signal is an audio signal, the angle modulated audio signal may be directly output to a listener at the demodulator. A multitude of applications exist for the present invention including Lincompex communication.

Abstract: At least two information waveforms are transmitted over the same communications channel using Lincompex techniques. Each of the information waveforms are modulated using Lincompex techniques to generate compressed information waveforms and associated control tones. The compressed information waveforms have the same frequency band. The compressed information waveforms and associated control tones are arithmetically combined, and transmitted over a transmission medium. These signals are then received from the transmission medium. A plurality of Lincompex expanders demodulate the received signals using Lincompex techniques and one of the associated control tones.

Abstract: A system and method for calibrating telecommunications systems employs frequency hopping techniques, and more particularly, employs linked compressor-expander (Lincompex) techniques in the transmission of any combination information waveform such as that generated by voice or digital data. A calibration tone sent at each channel frequency is compared against a reference frequency. Based on the results of the comparison, the information waveform is frequency compensated. Alternately, a calibration tone sent at an initial channel frequency is compared to a reference frequency to determine at total frequency error. The system then predicts the total frequency errors for successive channel frequencies. The system frequency compensates the information waveform based on the determined and predicted total frequency errors.

Abstract: A linked compressor-expander (Lincompex) system and method varies the power of the control tone signal to maintain the power of the signal supplied to the transmitter substantially constant. The system measures a parameter related to the power level of the compressed information signal output from the compressor and varies the power of the control tone such that the sum of compressed information signal power and control tone power is substantially constant. When the input information signal drops below the compression range of the compressor, the control tone amplitude is thereby boosted to maintain the combined information signal and control tone signal power more nearly constant, and thus improve performance during low input information signal power levels. During these low input information signal power levels, the power of the control tone S/N is boosted so as to maintain higher control tone at the receive, thereby improving demodulator performance.

Abstract: A linked compressor-expander (Lincompex) circuit for use in telecommunications utilizes a frequency compensation circuit to frequency shift the total bandwidth of the whole communication channel to eliminate single side band "duck-talk" and data distortion in the transmitting of a complex waveform due to frequency drift or the detuning of the transmitter/receiver system. The demodulator includes an expander for expanding the compressed voice or data signal and a control tone conversion circuit for converting the received control tone into a frequency signal to be used by the expander. The control tone conversion circuit also determines the frequency error of a combination information waveform so that the frequency compensation circuit can carry out the proper frequency shifting process. A fading regulator is also provided to remove any audible level variations not removed by the automatic gain control circuitry in the receiver.

Abstract: A system for transmitting and receiving frequency modulated signals utilizes linked compressor/expander (Lincompex) techniques. The signal to be transmitted is first processed by a Lincompex modulator which infinitely compresses the signal and produces a control tone representative of this compression process. After being processed by the Lincompex modulator, the compressed signal is frequency modulated and transmitted. A receiver having a Lincompex demodulator is used to receive the modulated signal. The received signal is initially demodulated by a discriminator prior to being expanded by the Lincompex demodulator according to the received control tone.

Abstract: A linked compressor-expander (LINCOMPEX) circuit for use in telecommunications is implemented digitally. A speech compressor circuit in a modulator and a speech expander circuit in a demodulator controllably attenuate given syllables of a speech signal by values determined in response to binary input signals which collectively represent the amplitude of a given symbol of the speech signal. A control tone signal is generated by the modulator, and the demodulator is responsive to the control tone signal for operating the voltage attenuator circuit of the digital expander to thereby reconstruct the speech signal. Calibrate circuitry is provided for periodically detecting a test frequency of the control tone generator during a brief period prior to transmission of syllables of the speech signal. Also included is a data multiplexing circuit for transmitting and receiving data between speech syllables to optimize transmitter loading.

Abstract: A phase locked loop signal generator is especially adapted for synthesizing a selectable frequency signal for exciting an HF radio frequency transmitter to transmit over the seven marine telegraph bands. The signal generator includes an oscillator for providing a highly stable frequency standard. Another signal generator is responsive to the frequency standard and to frequency selector signals input by the operator for generating an exciter signal which is coupled to the transmitter for effecting the RF transmission within a predetermined frequency range.