Frequency Multiplier


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frequency multiplier

[¦frē·kwən·sē ′məl·tə‚plī·ər]
(electronics)
A harmonic conversion transducer in which the frequency of the output signal is an exact integral multiple of the input frequency. Also known as multiplier.

Frequency Multiplier

 

an electronic or, less frequently, electromagnetic device for delivering an output wave with a frequency that is an exact integral multiple of the input frequency. The ratio of the output frequency fout to the input frequency fin is called the frequency multiplication ratio m(m ≥ 2, and can be as large as several tens).

It is a characteristic property of frequency multipliers that if finis changed within a certain finite range, the factor m remains constant, as do some other parameters, such as the resonant frequencies of oscillatory circuits and resonators used as components of frequency multipliers. From this it follows that if for some reason the input frequency is increased by a sufficiently small increment Δfin, the increment Δfout will be such that Δfin/fin = Δfou/fout. This means that the relative instability of the oscillation frequency remains unchanged upon multiplication. This important property permits frequency multipliers to be used for increasing the frequency of stable oscillations (usually obtained from a quartz driving oscillator) in various radio transmitters, radar, and measuring equipment.

The most widely used types of frequency multipliers consist of a nonlinear device (such as a transistor, varactor, varicap, coils with ferrite cores, or an electron tube) and one or several electric filters. The nonlinear device changes the waveform of input oscillations. Consequently, the oscillation spectrum at the output of the device exhibits components with frequencies that are multiples of fin. These complex oscillations enter the input of the filter, which extracts the component that has the specified frequency and suppresses all other components. In real filters this suppression is incomplete, and unwanted, or spurious, harmonics with numbers other than m appear at the output of the frequency multiplier. This problem is alleviated if the nonlinear devices generate practically only the mth harmonic of fin. In this case the filter may sometimes be omitted; some frequency multipliers of this type use tunnel diodes and special electron beam devices. At m > 5, it is advantageous, from the point of view of power consumption, to use multistage frequency multipliers, in which the output oscillations of one stage serve as input oscillations for the next stage.

The operation of certain frequency multipliers is based on the synchronization of self-excited oscillators. Oscillations excited in such an oscillator have the frequency f0mfin, and become exactly equal to mfin when acted upon by oscillations of a frequency fin that enter the input of the oscillator. The disadvantage of such frequency multipliers is the comparatively narrow range of values for fin that can be used for synchronization. In addition to the types mentioned, radio pulse frequency multipliers have also found some application. Here, the radio pulses are shaped by the input oscillations of the frequency fin and are then fed to the input of an electrical filter.

The primary problem encountered in designing frequency multipliers is the reduction of phase instability of the output oscillations, caused by the random character of phase changes. Phase instability increases the relative frequency instability of the output as compared with the same value of the input. A rigorous design of frequency multipliers involves the integration of nonlinear differential equations.

REFERENCES

Zhabotinskii, M. E., and Iu. L. Sverdlov. Osnovy teorii i tekhniki umnozhitelei chastoty. Moscow, 1964.
Rizkin, I. Kh. Umnozhiteli i deliteli chastoty. Moscow, 1966.
Bruevich, A. N. Umnozhiteli chastoty. Moscow, 1970.
Radioperedaiushchie ustroistva na poluprovodnikovykh priborakh. Moscow, 1973.

I. KH. RIZKIN

References in periodicals archive ?
Zhan, "The investigation of W-band microstrip integrated high order frequency multiplier based on the nonlinear model of avalanche diode," Progress In Electromagnetics Research, Vol.
Frequency multipliers could be one of these devices," said Palacios.
Camargo, Design of FET Frequency Multipliers and Harmonic Oscillators, Artech House Inc.
Among the 42 cases, 14 were attributed to the horizontal multiplier equaling 0, and the remaining 28 were attributed to the frequency multiplier equaling 0.
The general method adopted to simulate a frequency multiplier is iterative and consists in decomposing the passive structures in several blocks that are analyzed separately with Ansys[R] High Frequency Structure Simulator (HFSS).
Branner, "Optimization of Active Microwave Frequency Multiplier Performance Utilizing Harmonic Terminating Impedances," IEEE Transactions on Microwave Theory and Techniques, Vol.
One way to minimize filter design problems is to use a comb generator that includes a phase-locked frequency multiplier.
This in-line millimeter-wave frequency multiplier covers the 18 to 60 GHz frequency range.
The AMMP-6120, a 6 GHz to 20 GHz times-2 frequency multiplier, takes a 3 GHz to 10 GHz input signal and doubles it to 6 GHz to 20 GHz with integrated amplification, matching, harmonic suppression and bias network.
The enhancements include a newly developed signal data processor, higher-power transmitter and low-power RF reliability and maintainability improvements including a new frequency multiplier, greater sensitivity and wider dynamic range.
A generalized circuit schematic of a MESFET frequency multiplier is shown in Figure 1.
Figure 1 depicts the frequency coverage of the passive and active frequency multiplier line.

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