摘要:
The present invention is an electronic thermostat having correction for the self heating due to the semiconductor switching device used to switch a temperature modifying apparatus on. This invention includes a semiconductor power switching device disposed on an upper portion of a vertically oriented circuit board, a first thermistor disposed on the circuit board at a lower portion thereof remote from the semiconductor power switching device, and a second thermistor disposed on the circuit board at a portion intermediate between the semiconductor power switching device and the first thermistor. A corrected ambient temperature is generated from the temperature indicated by the first thermistor and the difference in indicated temperature between the second thermistor and the first thermistor. The state of the semiconductor power switching device is then controlled based upon the relationship between the corrected temperature and a desired temperature.
摘要:
The present invention is a method for specifying a constant in a digital electronic system. This technique employs the ratio of resistances between a reference resistor and a constant specifying resistor. The time constant of the constant specifying resistor and a capacitor is measured by discharging the capacitor, charging the capacitor through the constant specifying resistor and counting the number of predetermined time intervals required for the voltage across the capacitor to reach a predetermined threshold voltage. A similar time constant measurement is made for the reference resistor and the capacitor. The same conditions are employed as far as possible during these two measurements to insure the only differences are in the value of the resistances. The externally specified constant is computed from the digital ratio of the time constant of the constant specifying resistor and the time constant of the reference resistor. This technique is particularly adapted for use in a microprocessor system having several tristate output lines.
摘要:
A video time-shifting system characterized in having a continuous recording track accessed by separate, asychronous read and write facilities enables playback of a video program to commence from any point in the program while continuing to be recorded in real time, thus providing VCR-like program control features such as PAUSE/RESUME, REWIND, and FAST FORWARD. A memory is used to store information relating to various points in the program so that even upon receipt of multiple PAUSE commands, the system automatically keeps track of correct program re-entry. In the preferred embodiment, the storage means takes the form of a continuous recording track in a magnetic disk drive. To prevent discontinuities associated with the recording and reproducing of material representative of the video program, the system preferably incorporates a plurality of write heads, each associated with a different recording track, and the system automatically switches from one write head to another so as to effectively link the different recording tracks into a single, continuous recording track. Although program information may be stored in analog form, digital storage is used in the preferred embodiment along with data compression to increase recording capacity. The system preferably further includes a video display generator to output for viewing on the display device visual indicia relating to the program and, additionally, symbols relating to one or more points in the program and/or the time-shifted version thereof.
摘要:
The present invention is a technique for forming a signal representing the operator adjustment of a potentiometer. This technique consists of measuring the reference time constant of the resistance between the fixed terminals of the potentiometer and a capacitor, measuring the variable time constant of the resistance of potentiometer between a fixed terminal and the terminal variable by an operator setting and this same capacitor, and again measuring the reference time constant of the resistance between the fixed terminals of the potentiometer and the capacitor. These time constant measurements are made by discharging the capacitor, charging the capacitor through the appropriate terminal of the potentiometer and measuring the time required for the voltage across the capacitor to reach a predetermined threshold level. This measurement sequence is repeated if the two measures of the reference time constant differ by more than a predetermined amount. The digital ratio of the variable time constant and the reference time constant is then calculated. This digital ratio is the representation of the operator adjustment of said potentiometer.
摘要:
The present invention is a technique for forming a digital signal representing an environmental condition. The technique consists of measuring the variable time constant of an analog sensing device having a variable resistance dependent upon the environmental condition and a capacitor as well as measuring the reference time constant of a precision fixed resistor and the same capacitor. The time constants are measured by discharging the capacitor, charging the capacitor through the appropriate element and measuring the time for the voltage across the capacitor to reach a predetermined level. Lastly, the digital ratio between the two time constants is formed. This digital ratio is the digital representation of the environmental condition sensed by said analog sensing device.
摘要:
The present invention is a technique for thermostatic control of a temperature modifying apparatus such as a heating unit or an air conditioning unit. This technique involves measuring the ambient temperature, generating an error signal based upon the difference between a set point temperature and the measured ambient temperature, operating the temperature modifying apparatus according to the error signal, and adjusting the set point temperature based upon the time history of the error signal. In accordance with the preferred embodiment of the present invention, the temperature modifying apparatus is operated during the next cycle interval with a duty cycle proportional to the error signal at the start of the cycle interval. In the preferred embodiment the set point is adjusted via an adjustment quantity which is increased if the difference between a desired temperature is of one sense decreased if the difference is of the opposite sense and maintained unchanged if the desired temperature equals the measured temperature, with the adjustment quantity maintained within a predetermined band.
摘要:
A video recorder, adapted for use in conjunction with a remotely controllable unit associated with television recording and/or viewing, contains a remote-control signal transmitter to transmit control codes to the associated unit, and means to analyze the operation of the associated unit in response to the control codes. An electronic controller causes the transmitter to transmit test codes to the associated unit, then analyzes the resulting operation of the associated unit to determine its control codes, which it stores in a memory for later use.
摘要:
To initialize a remote control device for use in a particular installation, initialization parameters are entered relating to the relationship between user input codes and equipment to be controlled. In the preferred embodiment involving video recorder equipment, the initialization procedure concerns the video channels available to the recorder and remote control codes associated with the operation of the recorder using a receive-only modem on the device attached to a phone jack, initialization is performed by dialing up a remote location with a touch tone phone. At the remote end a computer sends selected audio response signals to the telephone receiver requesting that the user key in information using the touch tone pad. The computer then transmits the appropriate signals to the memory of the remote device to initialize it.
摘要:
A thermostat for generating control signals for a furnace, air conditioner, or the like, employs a constant frequency, periodically alternating electrical source and an oscillator incorporating an element having a thermal-sensitive electrical characteristic so the oscillator frequency varies as a function of the ambient temperature. A comparator receives the two outputs and generates a signal representative of the ambient temperature. The stable output is also provided to dividing circuits to generate a signal representative of the time that is used to interrogate a digtal memory storing a desired temperature-time period, such as a week or month. The ambient temperature signal is compared with the desired temperature signal to generate an output control signals. A display provides a read-out of time and temperature and is used along with a keyboard or the like in programming the memory.
摘要:
An electronic thermostat including a stored program of desired temperatures and predetermined maximum and minimum temperatures. The stored program of desired temperatures is selectable as either a program of heating temperatures or a program of cooling temperatures. When in the heating mode controlled by a program of desired heating temperatures, the cooling mode is entered and the air conditioner is energized if the actual temperature exceeds a predetermined temperature. The control temperature in this cooling mode has a predetermined relationship to the programmed temperature in the heating mode. Similarly, if the thermostat is in a cooling mode and the actual temperature falls below another predetermined temperature which is lower than the first predetermined temperature, then the thermostat enters the heating mode and energizes the furnace. The control temperature in this case bears a predetermined relationship to the programmed cooling temperature. In a further embodiment, the air conditioner is actuated if the actual temperature exceeds a predetermined maximum temperature regardless of the mode of the thermostat. In a still further embodiment, the heater is actuated when the actual temperature falls below a predetermined minimum temperature regardless of the mode of the thermostat.