Jefferson Davis grew up in Massachusetts and New York.
A voltage-controlled filter -LRB- VCF -RRB- is a processor , a filter whose operating characteristics -LRB- primarily cutoff frequency -RRB- can be controlled by means of a control voltage applied to control inputs .. filter. filter ( signal processing ). voltage. voltage. cutoff frequency. cutoff frequency. It can be considered to be a frequency-dependent amplifier .. Although popularly known for their use in analog music synthesizers , in general , they have other applications in military and industrial electronics .. A VCF allows its cutoff frequency and Q factor -LRB- resonance at the cutoff frequency -RRB- , to be continuously varied ; the signal outputs may include a lowpass response , a highpass response , a bandpass response , and a notch response .. cutoff frequency. cutoff frequency. Q factor. Q factor. lowpass. lowpass. highpass. highpass. bandpass. bandpass. notch. notch filter. The filter may offer a variable slope which determines the rate of attenuation outside the bandpass , often at 6dB / octave , 12dB / octave -LRB- a ' 2 pole ' filter -RRB- or 24dB / octave -LRB- a ' 4 pole ' filter -RRB- .. filter. filter ( signal processing ). bandpass. bandpass. This is also varied by the Q.. In modular analog synthesizers , filters receive signal input from signal sources , including oscillators and noise , or the output of other processors .. oscillators. Electronic oscillator. By varying the cutoff frequency , the instrument passes or attenuates partials .. cutoff frequency. cutoff frequency. In some popular electronic music styles , `` filter sweeps '' have become a common effect .. filter. filter ( signal processing ). These sweeps are created by varying the cutoff frequency of the VCF -LRB- sometimes very slowly -RRB- .. cutoff frequency. cutoff frequency. Controlling the cutoff by means of a transient voltage control , such as an envelope generator , especially with relatively fast attack settings , may simulate the attack transients of natural or acoustic instruments .. voltage. voltage. envelope generator. envelope generator. Historically , VCFs have included variable feedback which creates a response peak -LRB- Q -RRB- at the cutoff frequency .. cutoff frequency. cutoff frequency. This peak can be quite prominent , and when the filter 's frequency is swept by a control , partials present in the input signal resonate .. filter. filter ( signal processing ). Some filters are designed to provide enough feedback to go into oscillation , and it can serve as a sine-wave source .. ARP Instruments made a multifunction voltage-controlled filter module capable of stable operation at a Q greater than 100 ; it could be shock-excited to ring like a vibraphone bar .. filter. filter ( signal processing ). voltage. voltage. ARP Instruments. ARP Instruments, Inc.. Q was voltage-controllable , in part by a panel-mounted control .. voltage. voltage. Its internal circuit was a classic analog computer state variable `` loop '' , which provided outputs in quadrature .. A VCF is an example of an active non-linear filter  : however , if its control voltage is kept constant , it will behave as a linear filter .. filter. filter ( signal processing ). voltage. voltage. active. active filter. non-linear filter. non-linear filter. linear filter. linear filter