CN101330290A - Device for generating wideband microwave local oscillation signal - Google Patents

Abstract

The invention relates to a broadband microwave intrinsic signal generator. A phase lock loop chip with a built-in voltage controlled oscillator VCO forms a feedback lock phase with small step and low stray used for the generation of intrinsic signals. The feedback lock phase is subjected to frequency division of lock phase and is in phase comparison with a reference signal generated by VCXO, to generate control voltage. After the feedback lock phase is filtered by the loop circuit of an external pole point, the feedback lock phase is returned to the built-in voltage controlled oscillator VCO of the phase lock loop chip, thereby forming a phase feedback system; stable frequency is output by the phase lock loop, and is transmitted to a frequency multiplier through an LC high pass filter, and microwave intrinsic signal wave is outputted by the frequency multiplier through a secondary band pass filter and a high-frequency amplifier. The broadband microwave intrinsic signal generator has the advantages that by adopting the phase lock loop chip arranged with the built-in voltage controlled oscillator, the circuit board is more miniaturized, the integration degree of the system is more high, the cost is low, and inhibition functions of small stepped frequency and stray are achieved; the filter is integrated directly, thereby eliminating the fussy debugging process of the microwave. Furthermore, the consistency is better.

Description

A kind of device for generating wideband microwave local oscillation signal

Technical field

The present invention relates to a kind of local oscillation signal generator of microwave point-to-point communication, be under the prerequisite that guarantees phase noise and spuious index, adopt the two-in-one chip of phase-locked loop/voltage controlled oscillator, with the low-cost as much as possible device for generating wideband microwave local oscillation signal that produces the required 15GHz of microwave system.

Background technology

In the microwave point-to-point communication technology of PDH and SDH, in order existing communication band not to be crosstalked, general work is in the high-frequency microwave frequency range of 7GHz, 8GHz even tens G, signal transmission quality also there is strict requirement, the topmost index of expression channel transmission quality is the error rate, therefore, it is also growing to be used for the high-frequency local oscillation generating technique of microwave frequency conversion.

The microwave Point-to-Point Communication System has following requirement to combining frequently:

1) low cost budgeting:, also improved cost simultaneously and caused costing an arm and a leg though many microwave devices have fabulous index because concentrated most advanced now technology.And the low cost of microwave band is more and more important in communication in the reality;

2) good making an uproar mutually and spuious control performance: this is that the important indicator of microwave communication embodies, and directly has influence on the quality of communication.Mainly contain direct frequency doubling technology and microlock technology now, the former can accomplish index preferably, but broadband and little stepping are difficult for realizing; The latter can accomplish broadband and the near low cost realization of small step, but present phase-locked loop chip and voltage controlled oscillator all are difficult to accomplish high band;

3) good interference free performance and Electro Magnetic Compatibility;

4) be fit to produce in batches, conformity of production is good, easily debugging.

Based on above-mentioned background, the present invention combines phase-locked and advantage frequency multiplication, has realized the generation of low-cost local oscillator on veneer, and its performance index can satisfy system requirements, and production requirement is also lower.

Summary of the invention

Technical problem of the present invention is to provide a kind of cost low and in conjunction with the device for generating wideband microwave local oscillation signal of the advantage of phase-locked and frequency multiplication.

In order to solve above technical problem, the invention provides a kind of device for generating wideband microwave local oscillation signal, the phase-locked loop chip of one built-in voltage controlled oscillator VCO, the formation local oscillation signal takes place, the low spuious feedback of little stepping is phase-locked, the reference signal that produces with VCXO behind phase-locked frequency demultiplication is done bit comparison mutually, controls voltage to produce, behind the loop filtering by external limit, return the built-in voltage controlled oscillator VCO of phase-locked loop chip again, form a phase feedback system thus; The stable frequency of this phase-locked loop output is delivered to frequency multiplier behind the LC high pass filter, frequency multiplier is exported behind secondary band pass filter and high-frequency amplifier, output microwave local oscillation signal wave.

Described LC high pass filter and band pass filter are on monoblock microwave substrate circuit, integrated microwave distributed constant filter.

Superior effect of the present invention is:

1) adopts the phase-locked loop chip of built-in voltage controlled oscillator VCO: directly integrated voltage controlled oscillator in phase-locked loop, reduced peripheral voltage controlled oscillator, dwindled the area of printed circuit board, make more miniaturization of wiring board, the integrated degree of system is higher, reduced the overall cost of system, can produce in batches on a large scale;

2) locked loops of mixed decimal frequency division and the spuious inhibition of phase demodulation: this phase-locked loop produces the broadband phase locked source signal that is up to 3GHz, adopted differential integration structure decrease phase noise and parasitic signal, realize little stepping of frequency and spuious inhibit feature, thereby guaranteed the signal quality of phase locked source;

3) the integrated art of microwave filters of veneer: the distributed constant characteristic of utilizing microwave substrate, integrated microwave distributed constant filter on monoblock microwave substrate circuit, with the common high frequency microstrip filter design that forms of circuit board, omitted loaded down with trivial details microwave debug process, whole firm and hard now exempting from debugged, and consistency is better;

4) direct frequency multiplication and phase-locked combination technology: combining frequency multiplication and phase-locked advantage, and realize on veneer, is prerequisite with outstanding electromagnetic compatibility EMC performance design.

Description of drawings

Fig. 1 is a circuit block diagram of the present invention;

Fig. 2 is a loop filtering circuit diagram of the present invention;

The number in the figure explanation

The 1-phase-locked loop chip; 2-VCXO;

The 3-loop filtering; The 4-LC high pass filter;

The 5-frequency multiplier; The 6-belt energy filter;

The 7-amplifier.

Embodiment

See also shown in the accompanying drawing, the invention will be further described.

As depicted in figs. 1 and 2, the invention provides a kind of device for generating wideband microwave local oscillation signal, the phase-locked loop chip 1 of one built-in voltage controlled oscillator VCO, the formation local oscillation signal takes place, the low spuious feedback of little stepping is phase-locked, the reference signal that produces with VCXO2 behind phase-locked frequency demultiplication is done bit comparison mutually, controls voltage to produce, behind the loop filtering 3 by external limit, return the built-in voltage controlled oscillator VCO of phase-locked loop chip 1 again, form a phase feedback system thus; The stable frequency of this phase-locked loop output is delivered to frequency multiplier 5 behind LC high pass filter 4, frequency multiplier 5 outputs are exported the microwave local oscillation signal wave behind secondary band pass filter 6 and high-frequency amplifier 7.

As shown in Figure 1, return phase-locked through internal feedback in the microwave signal that the built-in voltage controlled oscillator VCO of phase-locked loop chip 1 produces, the reference signal that produces with VCXO2 behind phase-locked frequency demultiplication is done bit comparison mutually, to produce control voltage, return the control voltage controlled oscillator VCO again behind the loop filtering 3 by external limit, form a phase feedback system thus, obtained stable frequency output.Phase-locked loop member such as what phase-locked loop chip 1 used is the LMX2531 series of NSC company, this chip is integrated high frequency divider, decimal frequency divider, phase discriminator, current pump and integrated especially voltage controlled oscillator VCO realize that the low spuious feedback of little stepping is phase-locked.

As shown in Figure 2, loop filtering 3 has adopted the passive quadravalence loop that adds limit, can effectively suppress the near-end of voltage controlled oscillator VCO and make an uproar mutually.

As shown in Figure 1, phase-locked loop output is delivered to frequency multiplier behind LC high pass filter 4, produce the microwave signal of higher frequency.The frequency of phase-locked loop output selects for use different band pass filter 6 can extract the doubly inferior signal of required difference through producing the multiple harmonic of first-harmonic behind the frequency multiplier 5 as required.

Described LC high pass filter 4 and band pass filter are on monoblock microwave substrate circuit, integrated microwave distributed constant filter.Because the circuit form that has adopted direct little band to print can low-costly be realized, and is easy to produce, adopting multistage amplification and frequency multiplication is for better spuious inhibition and higher local oscillation power output are provided.

Claims (2)

1, a kind of device for generating wideband microwave local oscillation signal is characterized in that:

The phase-locked loop chip of one built-in voltage controlled oscillator VCO, the formation local oscillation signal takes place, the low spuious feedback of little stepping is phase-locked, the reference signal that produces with VCXO behind phase-locked frequency demultiplication is done bit comparison mutually, to produce control voltage, behind the loop filtering by external limit, return the built-in voltage controlled oscillator VCO of phase-locked loop chip again, form a phase feedback system thus; The stable frequency of this phase-locked loop output is delivered to frequency multiplier behind the LC high pass filter, frequency multiplier is exported behind secondary band pass filter and high-frequency amplifier, output microwave local oscillation signal wave.

2, by the described device for generating wideband microwave local oscillation signal of claim 1, it is characterized in that:

Described LC high pass filter and band pass filter are on monoblock microwave substrate circuit, integrated microwave distributed constant filter.

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