Abstract: An electronic ballast is powered by power source (102) and (104). The ballast controls the electrical power supplied to a gas discharge lamp (116), providing the voltages and currents required to start, warm-up and operate the lamp (116). Line power conditioner (100) reduces interference and harmonic generation, and provides a source of DC power (103), which may be regulated. DC power (103) is applied to inverter (105), which generates a square-wave voltage at a variable frequency determined by control circuit (200). Inverter (105) output is connected to resonant circuit (600) consisting of series inductor (110), series capacitors (112) and (118), and parallel inductor (114), across which gas discharge lamp (116) is connected. Operation begins with inverter (105) running at a frequency initially near but above the unloaded series resonance frequency of resonant circuit (600). Controller (200) reduces the frequency until resonant circuit (600) gives sufficient voltage to start lamp (116).

Abstract: Contained within a single housing (120), is a transducer (100) for receiving an acoustic signal, an analog-to-digital converter (108), which changes the output of transducer (100) into a series of digital pulses representing the incoming acoustic signal. The output of the system may be in serial form. This serial output (114) is transmitted (116) to a remote receiver (122) by wires, light, optical fibers, or as radio waves. The receiver's (122) output (124) is applied to a digital system (130), which processes or reconstructs the acoustic signal. The system may include a digital signal processor (300) within the housing (120) for processing the signal (110) prior to transmission. The analog to digital converter may be a delta-sigma oversampling type, or a sub-ranging floating point type, or use adaptive differential pulse code modulation. Power may be derived remotely by transmission over the signal medium.

Abstract: A self-contained, real-time spectrum analyzer performs the function of spectrum analysis on one or more analog electrical signals. The analyzer consists of an oversampling analog-to-digital converter 104, which converts the input signal 100 to digital form. The digital signal enters a digital signal processing integrated circuit microprocessor 108, which is operated by a stored program 112 that includes a spectrum analysis program 116. The output 122 of the digital signal processor 108 can be converted to analog signals by digital analog converters 124 for display on an external oscilloscope. A variable frequency oscillator 200 controls the sampling of the analog-to-digital converter 104, providing continuously variable analysis bandwidth. The output of the digital signal processor 108 can be applied to a display register and driver 300, which changes the output into a data format 302 suitable for use by a flat screen display 304.

Abstract: Improvement for power supplies include a protection circuit having a first L-C filter network, a second L-C filter network and a voltage clamping device such as a zener diode which is disposed between the two L-C filter networks. The protection circuit reduces the magnitude of overvoltage input transients which might otherwise damage the internal components of the inverter. For generating very high output voltages, the power supply includes a high voltage transformer and a Crockoft-Walton voltage multiplier coupled thereto. The high voltage transformer is coupled to an inverter through a coupling circuit which includes a capacitor in one leg of the primary winding and a parallel connected resistor/inductor in the other leg of the primary winding of the high voltage transformer. The high voltage transformer is formed of a multi-sectioned bobbin which is defined around an axially extending core.

Abstract: Improvement for power supplies include a protection circuit having a first L-C filter network, a second L-C filter network and a voltage clamping device such as a zener diode which is disposed between the two L-C filter networks. The protection circuit reduces the magnitude of overvoltage input transients which might otherwise damage the internal components of the inverter. For generating very high output votlages, the power supply includes a high voltage transformer and a Crockoft-Walton voltage multiplier coupled thereto. The high voltage transformer is coupled to an inverter through a coupling circuit which includes a capacitor in one leg of the primary winding and a parallel connected resistor/inductor in the other leg of the primary winding of the high voltage transformer. The high voltage transformer is formed of a multi-sectioned bobbin which is defined around an axially extending core.

Abstract: A system for providing remote program selection by a held caller in a telephone hold program system wherein a caller's line is connected to a holding circuit and a program is transmitted to the held caller. When a line is being held by the holding circuit, a hold detector causes an announcement to be coupled to the held line for instructing the held caller for remotely selecting one of a plurality of programs. The held caller sends select signals, in the form of voice or tone data, which are decoded and used to select the desired program source to be coupled to the held line. The system includes a remote volume control wherein a command signal sent by the held caller controls the volume level of the program supplied.

Abstract: An electronic ballast for starting and operating gaseous discharge lamps from a low voltage d-c source which employs a regulated inverter providing controlled high ignition voltage, constant current warm-up and constant wattage operation for one or more lamps.