Abstract: A signal phase shifting circuit shifts the phase of an input signal, such as a STROBE signal, based on a reference signal, such as a CLOCK signal, to facilitate, for example, receiving of double data rate data. The signal phase shifting circuit includes a reference signal period dividing circuit having a feedback delay matching array operatively coupled to one of a plurality of voltage control delay lines. This signal phase shifting circuit also includes a variable delay circuit that provides a phase shifted output signal, such as a phase shifted STROBE signal, that includes a delay stage in a phase shifted output signal drive buffer coupled to the delay stage, such as a voltage control delay line. The feedback delay matching array includes a plurality of serially coupled buffer stages operatively coupled to compensate for delay variations associated with the phase shifted output signal drive buffer in the variable delay circuit.

Abstract: A method and apparatus for providing very small changes in the output oscillation of a controlled oscillation circuit, which may be used in a phase locked loop circuit, is accomplished by a phase-shifting controlled oscillator that includes an oscillation circuit and a selection circuit. The oscillation circuit generates a plurality of oscillations that are of approximately the same frequency and are approximately equally phase shifted from one another. The selection circuit is operably coupled to receive the plurality of oscillations and selects one of them to be the output oscillation based on a control signal. The very small change in the output oscillation occurs when the selection circuit, based on the control signal, selects another one of the oscillations to be the output oscillation. When the change happens, a single pulse is stretched by the phase difference between the “old” output oscillation and the “new” output oscillation.

Abstract: A method and apparatus for providing serial transmission of a parallel input is accomplished by a parallel input serial output transmitter that includes a shift register operably coupled to receive a parallel input and to provide data serially to a gating circuit. The gating circuit, based on the state of the data it receives, generates a drive signal which causes a switching circuit to route current from a first current source to a second current source over different paths to produce a serial output. A bias circuit is coupled to the switching circuit to bias the serial output to a desired level.

Abstract: A programmable frequency synthesizer comprised of a phase locked loop (PLL) including a current controlled oscillator (ICO), a level translator for receiving output signals from the ICO wherein the output signals have a finite slew rate, a reference source of signals, a phase-frequency detector for receiving signals from the reference source and output signals generated by the level translator and for providing pulse signals to the ICO having pulse widths which are directly proportional to phase difference between the signals from the reference source and the output signals from the level translator, and apparatus for varying the slew rate of the output signals from the ICO wherein the duty cycle and thus the frequency of output signals of the level translator may be varied.