摘要:
The invention relates to transceiver comprising a sub-sampling based frequency synthesizer with a sampling frequency f smp , configured to generate M different output signals 3 for use as a carrier signal for transmission and/or a signal with a channel frequency for reception. M is an integer greater than 4, each output signal has a corresponding predefined frequency. The predefined frequencies are within a frequency band with a predefined bandwidth CFR. CFR is greater than f smp . The frequency synthesizer comprises a frequency shift unit configured for shifting a version of the output signal over a predefined frequency shift f shift to obtain a frequency shifted signal which is supplied to a sampling unit of the sub-sampling based frequency synthesizer, wherein -f smp /2 f shift +f smp /2. The frequency shift unit is configured to use for the generation of each of the N different output signals a corresponding predefined frequency shift f shift .
摘要:
Beschrieben und dargestellt ist eine Schaltungsanordnung zur Erzeugung von eine breitbandige Frequenzrampe bildenden hochfrequenten Ausgangssignalen, mit einem Referenzoszillator (1), einem Phasendetektor (2), einem Schleifenfilter (3), einem VC-Oszillator (4) zur Erzeugung der Ausgangssignale, einem Frequenzteiler (5), einem Abwärtsmischer (7) und einem Lokaloszillator (8) zur Erzeugung eines Lokaloszillatorsignals, wobei der Referenzoszillator (1), der Phasendetektor (2), das Schleifenfilter (3), der VC-Oszillator (4), der Frequenzteiler (5) und der Abwärtsmischer (7) zu einem Phasenregelkreis gehören, der Frequenzteiler (5) und der Abwärtsmischer (7) im Rückkoppelpfad des Phasenregelkreises liegen, der Abwärtsmischer (7) die Ausgangssignale und das Lokaloszillatorsignal mischt und die Frequenz des Ausgangssignals durch Variation des Teilungsverhältnisses des Frequenzteilers (5) einstellbar ist. Erfindungsgemäß wird mit Hilfe der einstellbaren Frequenz des Lokaloszillatorsignals die Kennlinie des Ausgangssignals verbessert.
摘要:
A variable frequency synthesizer and method of outputting the variable frequency is disclosed. The synthesizer comprises a first reference frequency, a direct digital synthesizer (DDS) receiving the first reference frequency and outputting a tuned frequency, a variable frequency comb generator receiving the tuned frequency and outputting a variable frequency comb comprised of a plurality of comb lines, a mixer receiving the variable frequency comb and a signal from an oscillator and outputting an intermediate frequency, a phase lock loop (PLL) receiving a second reference frequency and the intermediate frequency and outputting a phase lock signal, and the oscillator receiving the phase lock signal and outputting a variable synthesized frequency.
摘要:
An apparatus and method for providing an output signal. The apparatus comprises an input for receiving a reference signal, an oscillator for providing an output signal, and an offset signal generator for frequency multiplying the reference signal to generate an offset signal that has a plurality of frequency products in a plurality of frequency bands. The apparatus further includes a mixer for mixing the offset signal with the output signal to produce a combined signal, an offset frequency selector for controllably selecting a frequency band of the offset signal, and a difference detector for detecting a difference between the reference signal and the combined signal and for providing a control signal to the oscillator based on the detected difference.
摘要:
The present invention provides a system, apparatus and method for recovering a client signal clock. The present invention is able to more effectively remove jitter within a clock signal by providing a phase shifting element in the feedback of a PLL system to compensate for sudden changes in an input reference clock. The PLL system provides flexible clock recovery so that it can accommodate various payload types because it extracts a client clock signal independent of a corresponding justification count number.
摘要:
A fractional-N offset phase locked loop (FN-OPLL) is provided. The N-OPLL includes a fractional divider, a phase detector, a loop filter, a voltage controlled oscillator (VCO), and feedback circuitry. Combiner circuitry (108) combines an initial fractional divide value and a modulation signal to provide a combined fractional divide value. Based on the combined fractional divide value, the fractional-N divider (96) divides a reference frequency and provides a divided reference frequency to the phase detector. The phase detector (98) compares a phase of the divided reference frequency to a phase of a feedback signal to provide a comparison signal. The comparison signal is filtered by the loop filter (100) to provide a control signal to the VCO, where the control signal controls a frequency of an output signal of the VCO. The output signal is processed by the feedback circuitry to provide the feedback signal to the phase detector.
摘要:
There is disclosed a phase locked loop comprising: a phase frequency detector for receiving as a first input a reference signal and for generating a control signal; a voltage controlled oscillator for receiving the control signal and for generating a signal defining an output frequency, a feedback path connecting the output signal to a second input of the phase frequency detector; and a digital accumulator for generating the reference signal under the control of an accumulator reference clock. [Figure 3]
摘要:
A precision oven-controlled crystal oscillator (10) uses an adjustment feedback signal that, when mixed with a reference signal from a stable reference oscillator (32), accurately controls the generation of an output signal from a voltage controlled crystal oscillator (38). An OCXO according to the invention has high stability and high accuracy. The digital OXCO can be manufactured at low cost, and is particularly beneficial for Code Division Multiple Access (CDMA) base station applications in cellular communication networks and the like.
摘要:
The programmable frequency control system presented herein provides frequency programmability and phase noise reduction for signals generated by a plurality of frequency programmable phase-locked loops (PLLs). In general, a modulated data stream input to each of the plurality of PLLs controls the frequency of the signal output by the PLLs. The solution presented herein reduces the phase noise by introducing a time shift to the modulated data stream applied to at least some of the PLLs so that at least some of the PLLs receive time-shifted versions of the modulated data stream relative to other PLLs. In so doing, the solution presented herein decorrelates the quantization noise generated by the plurality of frequency programmable PLLs.
摘要:
A variable frequency synthesizer and method of outputting the variable frequency is disclosed. The synthesizer comprises a first reference frequency, a direct digital synthesizer (DDS) receiving the first reference frequency and outputting a tuned frequency, a variable frequency comb generator receiving the tuned frequency and outputting a variable frequency comb comprised of a plurality of comb lines, a mixer receiving the variable frequency comb and a signal from an oscillator and outputting an intermediate frequency, a phase lock loop (PLL) receiving a second reference frequency and the intermediate frequency and outputting a phase lock signal, and the oscillator receiving the phase lock signal and outputting a variable synthesized frequency.