Abstract: In monitor circuitry, a simple circuit separates out the horizontal synchronization pulses from the composite synchronization signal and removes undesired horizontal synchronization pulses during the vertical blanking period. By using a pulse-width modulated signal having the same frequency as the horizontal rate but not necessarily with the same phase, and having at least a 50% duty cycle, the undesired pulses are gated out before being coupled to the horizontal synchronization circuit of the monitor, thus, the monitor system will not attempt to lock at a double frequency, nor cause visible distortion of the raster. The effect of the pulse width modulated signal is inhibited when a user changes the horizontal synchronization frequency and until the monitor achieves lock on the new frequency.

Abstract: A game device consisting of a large band of very strong and highly elastic material which is supported in use by the torsos of the players. When a player (or players) leaves his or her position against the band and dashes across and into another portion of the band, the force of the body's impact causes other players to be propelled across the band, repeating the sequence for a specified time period or indefinitely. No other pieces of equipment are required for the game, and no special field layout or other construction is necessary.

Abstract: A warning or alerting device for a manually operated, concrete finishing tool may provide a flashing light, a beeping signal or both when the tool is being operated. The device may be attached to the extended handle of the tool. Use of the warning device will help prevent injury to coworkers or bystanders from the long handle of the tool as the working end of the tool is drawn back toward the operator.

Abstract: Unwanted electric fields in the area in front of a CRT can be produced by flyback voltage pulses which occur across the horizontal deflection coils and are coupled to the inner DAG coating of the CRT. The unwanted fields can be eliminated by providing voltage pulses equal and opposite to the causative voltage pulses and applying the provided voltage pulses to the inner coating and the anode button, leaving no fields to be cancelled in the relevant area.

Abstract: A control circuit in an AM stereophonic receiver examines a detected signal for occurrences of overmodulation and, when a first given level of overmodulation is reached, begins to turn down the correction signal used in the demodulation and, if overmodulation continues, would eventually eliminate the correction signal. At a second given level of overmodulation, the circuit will begin to attenuate the stereo difference signal from the receiver output and eventually eliminate it. When the overmodulation is reduced, operating conditions return toward normal.

Abstract: An FM receiver as used in communciations systems includes a blanking switch for deleting noise pulses and a delay device for delaying the detected pulses so that blanking can occur at the correct time. The circuit receives and detects noise pulses and amplifies them at several gain levels simultaneously. Each amplified pulse which passes a predetermined level causes a trigger signal pulse to be coupled to a ramp generator. The trigger signal pulses are coupled through a combination of flip-flops and voltage controlled switches, and each noise pulse enables a ramp signal of a predetermined maximum but having a rise time which is a function of the detected noise pulse amplitude. The ramp signal length is used to provide blanking switch control signals of an appropriate length to blank out substantially all significant noise pulses.

Abstract: The correction signal of the AM stereo system is filtered through a lowpass filter thus providing compatible signals at all normal modulation levels and frequencies, but allowing the signal to become pure quadrature at high frequency, high modulation levels. The inverse of the process can be utilized in the receivers if desired. The improvement is needed only for narrow channel or restricted sideband broadcasting.

Abstract: A variable Q filter network in an AM stereophonic receiver provides elimination of any adjacent channel carrier interference while providing the function of a tone control, either automatic or manually controlled. Parts count and costs, IC pinouts and the possibility of intermodulation are all reduced.

Abstract: A correction control circuit for use in compatible AM stereophonic receivers of the type utilizing a cosine correction signal to remove inherent distortion from the received and detected signals. During periods of weak or noisy signals or when co-channel interference is present, excess cosine correction signal causes a reduction in the amount of stereo difference signal component in the output signals, and in the amount of correction provided. In a worst case signal situation, there will be no difference signal component in the output and the monophonic output not be corrected.

Abstract: The circuit utilizes combinational logic and latching circuits to prevent damage to the regulator or to the battery of an automotive ignition system due to a serious fault such as the ignition being turned "on" but the engine/alternator not rotating. A fixed duty cycle control signal is added to the control signal for the field excitation current only when a serious fault is detected, thus limiting battery drain and excessive temperature in the regulator module but not shutting the whole system down. The system thus provides the desirable "limp-home" capability.

Abstract: The system requires the use of the permanent ID of the requesting unit in every channel request made on a control channel before every transmission. The channel grant will include the ID along with the channel number and these may be recorded for possible later reference. A channel assignment is retained for a brief period after each transmission, allowing a conversation to be continued on the same channel without a break. Units can access the control channel with a channel request and be assigned a channel even while the dispatcher is using the voice channel. In the case of a need for communication with a larger group, a dispatcher can form a temporary "patch" group of all involved units, with a temporary ID assigned to that group. A channel request from a member of the larger group must then include, not only the permanent ID of the requesting unit, but the temporary ID of the "patch" group.

Abstract: An analog divider circuit as for use in AM stereophonic receivers provides minimum phase variation with control voltage level change, by means of a feedback circuit. The division process is performed by subtracting logarithms of currents produced by the dividend and divisor voltages, then deriving the antilog of the difference or remainder. At the critical point in the process, where junction capacitances do not accurately track the change in the control level, cross-coupled capacitors stabilize the circuit by feeding back a signal from the circuit output to minimize any undesired phase changes.

Abstract: The tone detector provides accurate detection of a single predetermined tone frequency within a mixture of frequencies, utilizing a carrier signal source at a relatively high frequency. The high frequency signal is divided down to two frequencies, one just above and one just below the tone. The divider output is then maintained at the frequency of the tone by continuously adjusting the divisor number between the two divisor values. Multiplying the received signal or a portion thereof by the divider output provides a detect signal when the tone is present in the received signal with sufficient amplitude.

Abstract: In a stereophonic broadcasting receiver, a single indicator with two levels of illumination serves to provide indication of both accurate tuning and the presence of stereophonic signals. One signal or a combination of signals related to the tuning circuits of the receiver cause the indicator to be illuminated to a perceptible level. When, by use of a pilot tone detector, it is certain that stereophonic signals are being received, additional current is caused to flow through the indicator, raising the illumination to the maximum allowable level. The circuit has particular application to manually tuned receivers.

Abstract: An AM stereo transmitter with bandwidth limiting utilizes the detection of high frequency energy in the modulating signal to control the difference channel input to the stereo encoder.

Abstract: A re-regulation circuit operates in the environment of a vehicle alternator/charging system and cooperates with the standard regulator to prevent momentary loss of load from reducing the field excitation to such an extent that the alternator AC output is too low for proper functioning of such AC-dependent circuits as the tachometer circuit. Re-regulation is prohibited in the event of a true fault in the system. The temporary condition is not indicated to the user as a true fault.

Abstract: A door operator system includes up and down limit switches actuated to the closed position when the door reaches the up and down travel limits. A processor circuit within the operator is connected to the limit switches for ascertaining the position of the door. Bias circuits apply a bias to the processor when the limit switches are open. An indicator system comprising a pair of light emitting diodes connected across respective limit switches indicates the door position. A series impedance element common to both LED circuits prevents actuation of the control circuit by the light emitting devices.

Abstract: The AFC gain of the local oscillator of an AM stereophonic decoder is linearized by the use of difference channel (L-R) information for controlling the capacitance of two varactor-type devices coupled across and in series with the oscillator inductance coil. The improvement helps to prevent "falsing" of the pilot tone indicator and the mono/stereo mode circuitry, particularly at the ends of the tuning range of a manually tuned receiver.

Abstract: A trigonometric transform function generator provides a signal which is either the sine or cosine function of an inputted information signal. The function generator can be used in an FM system or in a new system of transform modulation, wherein the transform functions are used to derive the original information signal.

Abstract: In an AM stereo system wherein a low frequency pilot tone is added to the difference channel signal before modulation of the carrier, "image shifting" and audio distortion in a receiver, due to residual pilot tone signal, are removed by separating out a portion of the pilot tone after it has been filtered and phase shifed for enabling the stereo mode of operation. The separated signal is then inverted and delayed appropriately for each of the PLL and audio circuits.