Abstract: The invention provides a master controller to store and call up on command a plurality of setups for numerous satellites. An antenna is directed to a desired satellite, the polarization of the feed horn is changed to that of the signal to be received and a receiver or receivers are switched to the proper band, C or Ku. A transponder is selected as are audio and/or video frequencies, half or full transponder modes in the Ku band, and video reverse. The setup is recalled by an operator or by a timer which can call or set up at prescribed periodic intervals or on a one-time basis. An operator can change one or more parameters of a specific setup.

Abstract: A satellite signal identification system utilizes distinguishable unique coded identifiers impressed on a carrier sent from a transmitting ground station to be identified. The identifier is recieved and identified by the receiving station to specifically identify a particular underlying carrier signal for reception. The invention utilizes a data modem for transmitting to an earth relay satellite coded identification signals together with various data and error correcting information. An IF carrier signal may be combined with video and/or audio signals, such combined signals being relayed via satellite to the ground station. The MPU of a modem in the ground station finds its counterpart in the MPU of the downconverter that receives via a block downconverter the data, housekeeping and ID signals after the video has been removed. The downconverter first translates the satellite transponder frequency to an IF frequency and sequentially searches for a carrier and the PSK code.

Abstract: A dual conversion variable bandwidth telemetry receiver employs a phase locked loop which controls the second local oscillator to maintain lock on the carrier frequency; the phase locked loop employing a loop filter with a variable time constant integrator, the time constant of which can be varied as a function of receiver bandwidth and the integrator with its associated capacitor and resistor banks being employed in a sweep, i.e. search, oscillator circuit enabled when the carrier signal is lost. A coherent double-balanced mixer is employed to detect carrier lock and if lock is lost but the carrier is still detected, a rapid response anti-sideband circuit in the phase detector of the phase locked loop is employed to suppress the sidebands and greatly increase the probability of relocking on the carrier. A synchronous AM detector employs quadrature IF and reference signals at the same frequency to produce a dc signal when phase lock occurs; the signal falling rapidly upon loss of lock.

Abstract: A receive only, low cost, small size, frequency agile earth satellite ground station has the low noise amplifier, frequency agile receiver, head end modulator, motor control circuit and optional signal unscrambler disposed on circuit boards about a variable polarization antenna-to-low noise amplifier feed which together with the motor for controlling the feed polarization of the feed are all located in a weather insulating cannister at the focal point of the system antenna whereby the only elements of the system not located in the cannister are the antenna and a cable connected control console employed to select a desired channel and to select local or satellite reception located at the TV set. A motor control is provided which senses odd-or-even least significant bit of binary coded channel selection signals to determine if the feed polarization, control motor must be energized.

Abstract: A system in which automatic gain control is not applied to modify an incoming carrier signal over the first 40 dB of signal level, employs an AGC system in which a further signal is generated for further modification of the modified carrier signal to obtain the original carrier signal modified by a linear logarithmic response to the AGC signal over the entire signal range of the apparatus. In addition, automatic gain control signals derived from both an envelope AM detector and a synchronous AM detector are added together whereby a continuous AGC signal is generated regardless of the source of the signal.

Abstract: A multiple bandwidth quadrature type FM demodulator employs a double-balanced mixer supplied with a frequency modulated IF signal directly and through one of a selectable plurality of bandpass circuits each having a different bandwidth, having a linear phase shift versus frequency characteristic and producing a 90.degree. phase shift at the IF frequency whereby to produce at the output of the mixer a signal level that varies as a linear function of frequency of the input signal, the demodulator including a bias control circuit for the mixer to establish a normalized output for all filters at full bandwidth modulation and further including circuits for establishing a signal balanced with respect to ground or other reference potential regardless of the filter employed.

Abstract: A method of developing waveforms having the energy therein concentrated within a limited bandwidth and modems for generating, transmitting, and receiving digital data utilizing such waveforms as carriers. A set of mutually orthogonal basis signals are selected to maximize their energies within the channel, each is binary coded and stored in the modem. A set of optimized coefficients is stored and utilized to weight each basis function in a coding arrangement to define bytes of digital data. The coded and weighted basis functions for each successive byte are summed to form a composite signal and transmitted over the channel as an analog waveform. Stored basis signals at the receiving end are correlated with the received waveform to thereby extract the coefficients which are decoded to reproduce the transmitted bytes. Both coding gain and reduction of intersymbol interference is achieved.

Abstract: A received video signal that has been inverted at the transmitter is reinverted by the use of low cost pin diodes to reverse the ground and signal lead connections to the primary winding of a transformer operating at RF frequencies.

Abstract: A wave guide of an antenna feed assembly has a wave polarization rotary section comprising a plurality of closely spaced conductive pins extending across the diameter of the wave guide. A first group of such pins adjacent the output end of the wave guide to an amplifier are stationary while a second plurality of pins are rotatable about the axis of the feed in progressive steps through each pin to 45.degree. positions selectively to one or the other side of the plane formed by the stationary pins to rotate one or the other of the 90.degree. polarized waves 45.degree. into the plane of the stationary pins and thence to the amplifier. The movable pins are received in a collar rotated by a conventional motor, the pins being located in slots of varying lengths in the collar so that each rotatable pin lies at the same angle to both of its adjacent pins.

Abstract: This disclosure relates to electronic devices, such as a television receiver, whose bandwidth is automatically reduced when the signal-to-noise ratio of the incoming signals becomes lower. Two circuits respectively sample the received video signals and the noise. The outputs of these two circuits feed a divider which divides one output by the other. A tuned filter (which follows an IF stage of the television receiver), which varies its bandwidth according to a control voltage fed to it receives the varying output voltage of said divider. The video and noise signals, which are fed to the divider, are both derived from the sync signal of the television receiver. Timing circuits control the operation of the system. One of these circuits distinguishes the sync signals from the equalizing pulses and eliminates the latter thereby reducing the error in the noise measurements.