Abstract: An apparatus includes a phase locked loop (PLL). The phase locked loop (PLL) has coarse tuning (CT), fine tuning-integer (FT-i), fine tuning fractional (FT-f), frequency modulator tuning-fractional (FMT-f), and narrowband (NB) modes of operation.

Abstract: A rubidium frequency standard control circuit which utilizes an initial sweep hand-off frequency locking process followed by a negative feedback loop for optimization of the stability of the voltage control oscillator employing the rubidium frequency standard.

Abstract: A frequency oscillator tuning process at the manufacturing stage is replaced with an adjustment of a resonant circuit in the frequency oscillator during an operation of the oscillator. The adjustment utilizes a crystal oscillator, a frequency oscillator such as a voltage-controlled oscillator (VCO), and a trimmer in a phase-locked loop configuration to determine a correction voltage required for an untrimmed VCO to operate at a nominally specified frequency by adjusting an input tuning voltage for a resonant circuit.

Abstract: An adjustable frequency oscillator with a wide tuning range which can be voltage or current controlled. A maximum tuning per feedback current is obtained by phase shifting a feedback signal by approximately 90 degrees with respect to the oscillating output signal, which is internally generated by the adjustable frequency oscillator. Over the frequency range of operation, the oscillation frequency of the oscillating output signal is linearly controllable. The adjustable frequency oscillator is also implemented as a ring oscillator and/or an oscillator with ranging.

Abstract: The present invention is directed to apparatus and methods for reducing transient signals in phase locked loop (PLL) circuits of central processing units. One aspect of the present invention is directed to a method and apparatus that disables a charge pump circuit in a phase locked loop circuit when a frequency change in the output signal of the PLL circuit is implemented to limit transient signals generated by the PLL. Another aspect of the present invention is directed to a method and apparatus for coordinating a change in divider values for frequency dividers in a PLL of a CPU to limit transient signals from the PLL.

Abstract: A programmable circuit for generating a clock signal is disclosed. The present invention provides a clock generator architecture that combines PLL-based clock generator circuitry with an on-chip EPROM in a monolithic clock generator chip. The clock generator allows for electrical configuration of various information including PLL parameters, input thresholds, output drive levels and output frequencies. The various parameters can be configured after the clock generator is fabricated. The parameters can be configured either during wafer sort or after packaging. The clock generator can be erased prior to packaging so programming can be verified.

Abstract: An inverter is connected between the control nodes of two transistors in a current mirror system which forms a closed current feedback loop. Any difference between the bias voltages at the input and output of the inverter is reduced to zero. The self-biasing inverter amplifier may comprise the active part of an oscillator but may also be used as a level shifter or a reference circuit.

Abstract: A stable sine wave oscillator circuit comprising two pairs of cross-coupled bipolar transistors in cascode, the collector electrodes of the transistors of each pair being interconnected by way of respective capacitors. Output signals in phase quadrature may be obtained from across these two capacitors.

Abstract: A Field Effect Transistor (FET) signal delay system with increased propagation delay time stability. This is accomplished by using a controlled voltage supply to power the amplifier stage. This voltage changes as the FET amplifier temperature increases in order to reduce the variation in propagation delay time, caused by the amplifier's gain and phase shift changes. By using this compensated amplifier as the delay element of a signal delay system, the propagation delay time stability is increased.

Abstract: A carrier rejection circuit for improving carrier rejection in a balanced modulator includes balun transformers, connected to the carrier signal port and the modulated signal port, which reduces parasitic carrier leakage by reducing the average voltages at the ports, offset adjustment circuitry, connected to the modulating signal port, which applies an adjustable offset voltage to the modulating signal to reduce in-phase parasitic carrier leakage and carrier leakage caused by offset voltage at the modulating port, and a reactance network, connected between the carrier signal port and the modulated signal port, for reducing quadrature-phase parasitic carrier leakage.

Abstract: In a method and a circuit arrangement for recovering a digital signal having digital pulses from a recorded signal which is read by a read head of a storage device, the shape of the recorded signal, being a reproduction of the digital signal, is compared with the shape of a normal read signal previously stored as a comparison pattern of voltage values. In the case of agreement, which is given on the presence of a certain correlation, the recorded signal is evaluated as a digital pulse and otherwise on non-agreement as a digital non-pulse.

Abstract: A circuit device for phasing an oscillator, which comprises a multivibrator having a transistor pair with the emitters coupled through a capacitor, comprises a normally open electronic switch controlled by a drive signal to close and inhibit the oscillator. This switch connects a voltage divider to the base of a transistor connected to one of the emitters to interrupt the loop positive feedback of the oscillator upon the voltage across the capacitor reaching a predetermined value.

Abstract: For driving gas discharge lamps (102, 104) having heatable filaments (102A, 102B, 104A, 104B), a circuit (100) has an inverter (132, 134) and a series-resonant LC oscillator (150, 158, 170) forming a self-oscillating inverter. The oscillator output provides filament-heating current through the filaments in series, and drives arc current serially through the lamps. A feedback transformer (174) with a winding (172) connected serially in the filament-heating current path controls the operation of the inverter. A voltage clamp (180, 182) limits the voltage applied to the lamps. The circuit does not require an output-coupling transformer to couple the output of the self-oscillating inverter to lamps, thus avoiding the added cost that the use of such a transformer would bring, while providing efficient, substantially fixed frequency operation of a wide variety of lamp loads, together with the ability to address a number of lamp fault modes. Alternatively, the lamps may be driven in parallel.

Abstract: A differential mixer oscillator employing two transistors in a differential pair as the sustaining amplifier for a quartz crystal resonator at some first high frequency. The bias current of the differential pair is modulated at a second high frequency derived from some second frequency generating source, typically a second quartz crystal resonator, and the product terms are available at the collectors of the two transistors for selective filtering. The differential mixer oscillator may be employed in multiples, and with a variety of current sources, such as a Colpitts oscillator circuit.

Abstract: An electrically tuned super-regenerative receiver (10) comprises a feedback type oscillator having a signal output and a signal input, phase shift components (30) connected in a feedback loop for coupling the signal output to the signal input to cause oscillations, and a quench oscillator (35) coupled to the signal input for switching the oscillator between an oscillating and a non-oscillating condition. A variable capacitance device (40), such as a varactor diode, is connected between the signal output and a reference potential (21), and a microprocessor (105) provides a tuning voltage (42) which is applied at the signal output for varying the current in the varactor diode, thereby varying the oscillator center operating frequency. The oscillator center operating frequency is detected by a spectrum analyzer (112) and compared to a desired center operating frequency by a controller (118).

Abstract: A high pressure lamp assembly having an improved structure for supporting the discharge tube while providing an opening bi-metallic switch for electrically disconnecting the auxiliary electrode. Metallic frames are disposed at the upper and lower ends of the discharge lamp to provide at least partial support to the discharge tube. A non-conductive bridge assembly is connected between the lead through of the auxiliary electrode and a conductive rod extending from the stem. The non-conductive bridge provides at least partial mechanical support to the discharge tube. Connected across the non-conductive bridge is the starting resistor and bi-metallic switch element. When the bi-metallic element is unheated, it provides electrical connection through the starting resistor to the auxiliary electrode. When heated by the heat from the discharge tube, the bi-metallic switch moves out of engagement with the ceramic bridge and thus breaks the electrical connection to the auxiliary electrode.

Abstract: A wordline driver circuit is shown for a DRAM, the circuit comprising a PMOS transistor structure having one contact coupled to a wordline, a second contact coupled to a negative voltage supply and a gate coupled to a control input, the transistor having an N-well about the gate, first and second contacts. An isolating structure is positioned about the N-well to enable it to be a separately controlled from surrounding N-well structures. Pulse circuits are coupled to the transistor for applying, when activated, a potential that enables the wordline to transition to a more negative potential. A bias circuit is also provided for biasing the N-well at a first potential and a second lower potential, the second lower potential applied when the pulse circuits are activated. As a result, body effects in the PMOS transistor are minimized while at the same time enabling a boost potential to be applied to the wordline.

Abstract: An FM demodulator circuit uses an oscillator to provide a switch control signal synchronized to an FM signal, and a current supply to provide differentially alternating currents at first and second outputs flowing through a commutator circuit to the first and second outputs of the FM demodulator circuit. The commutator circuit is responsive to the switch control signal for alternately switching the first and second outputs of the current supply between the first and second outputs of the FM demodulator circuit thereby providing an alternating current flowing in the first and second outputs of the FM demodulator circuit which has an average value over each half cycle of the switch control signal proportional to the deviation of the frequency of the FM signal from the free-running frequency of the oscillator.

Abstract: An optical system which provides wavelength tuning and which may be a spectrometer, monochromator or tunable laser uses a volume transmission diffraction element which is characterized by a periodic, spatial variation of refractive index or polarizability or other light transmission effecting parameter, and which is distributed throughout the volume of the element. The wavelength is tuned by (1) varying the angles of the incident and diffracted light symmetrically with respect to the periodic distribution in the element and/or (2) by varying the spatial period of the diffracting element's volume modulation distribution which is maintained symmetric with respect to fixed incident and diffracted beam angles.