Dyna-mite_sm 电路图.pdf

DYNAMITE COMPRES SOR/LIMITER/EXPANDER/ GATE OPERATI NG I NSTRUCTIONS RadioFans.CN 收音机爱 好者资料库 Contents Page 1.GENERAL INFORVIATION l.; bv-itnit. Specificatiolt- :-,- 1.3 Introductiontopittu-icsProcessing .: A. Overview B- Threshold/Attack/Release C. Detector Circuit D. Transient Matena ialResPonse. E. Release Circuit F. Gain Control Elements INSTALLATION 2.1 Connecting Dyna-Mite to Other Equipment Z.Z Accessories THEORY OF OPERATION 3.1 Block Diagram ;.; Cii.i, o.criPtion OPERATING INSTRUCTIONS 4.1 TheControls. : 4.2 UsingDvna-Mite-iiOpttutingModes .:.: 3 3 3 3 4 5 5 6 6 1 6 8 8 9 10 I I I u slIIg .l-,ryrr4-rYrrLv A. Limiting Functtons :;-;i 1. General U;f;t Apparent Level Control 2. Peak Limiting fot litoadcast/Disc Cutting 3. FM Pre-emPhasized Limrttng 4. DS Limiting B. ExpandingFunciions :- i.-c.,.iurNoi,.n1!i31,I1r;3B:?,x?ttt;ii;.:.:.:. 6. Noise Gating for Percussrve anrr rrcrri:;?;* Ftil 7. Noise CiiE or Noise Expandine Using FM/DS Filter 8. Noise ii#; ;dffiyie an Eiternal Equalizer C. Keying, otigii Ennttope Following 9. KeYing Effects 10. EnveloPe Following 1l 11 1l t2 t2 t2 13 13 13 13 13 13 l4 l4 l4 l;:. i.ru.tt.-Ettuelope Following :. ;. iilte.croliedNegativeLimiting .:.:. 15 15 15 15 5. 16 t7 18 19 6. 4.3Functional Modes Reference Chart MAINTENANCE 5.1 Brief Circuit Information 5.2 Adjusting the Trim PoH,:-:,-, o i:-i;*r Balance Trim (R18) 2. Threshold Trim (R24).:, ;. vdn n:.tion irim (R101) 5.3 Warranty ILUSTRATIONS 6.1 GraPhs of Control Function 6.2 Schematic Drawtng 6.3 Parts Overlay 15 15 6.4 Power SuPPIY RadioFans.CN 收音机爱 好者资料库 General Information 1.1 DESCRIPTION The Valley International DYNAMITE is a self-contained and self- powered multi-purpose processing device. In all, it is capable of operating in 18 specific modes, including the basic modes of Limiting, Expansion, De-essing, Noise Gating, Ducking, Keying, etc. In the Limiting mode alone, there are a number of specific derivations, such as Peak Limiting, Linear Integration Limiting, FM Pre-emphasized Limiting and Side Chain Controlled Limiting. Similar derivations are evident in the other basic operating modes. The selection of operating modes is straightforward and understandable, as indicated by three front panel switches, each having three positions. In each operating mode, full parametric control is afforded by four continuously variable controls. Thus, while being easy to operate, DYNAMITE is capable of satisfying the most critical of demands for performance. The device is fully metered, with an 8 element LED Gain Reduction Array, plus clipping indicator. Balanced input circuitry capable of + 24dBv is employed to assure compatibility with professional equipment, while the circuitry is structured to interface correctly to low level,/high impedance semi-pro components. The output circuit can deliver a full +21dBm into 600 ohm loads or transformers, yet can feed - l0dBv lines with excellent noise levels and compatibility. The circuitry employed represents the highest possible tech- nology, for excellence of performance in any system. Every effort has been put forth in the packaging of DYNAMITE to assure a simple, yet reliable interface: professional type ring/tip/sleeve jacks; 1101220 VAC operation; rugged steel and aluminum rack package for ease in installation. Stereo coupling is ac- complished by pressing a front panel switch. 1.2 DYNAMITE SPECIFICATIONS INPUT Signal Input Impedance: 94 kohm in parallel with 47 pF balanced, or 47 kohm in parallel with 47 pF unbalanced Input Level for *4 dB Output: Nominally -11d8 +19 dB 1 kHz sine input in bypass; -59 dB to +24 dB in limiting Maximum Input Level Before Clipping: +24 dB External Input Impedance: Same as signal input specification Maximum External Input Sensitivity: -40 dB for ducking and keying (depends upon threshold setting) OUTPUT Output Impedance: (40 ohm, unbalanced Maximum Output Level: +21 dBm (600 ohm) Quiescent Distortion +10 dB Input: <0.04% lkHz THD unity gain <0.3% SMPTE IMD unity gain (typically 0.l%) and Hum ( uni- source impedance = 1000 ohm): ELECTRICAL Power Supply Mains Requirement: 90 - 130 Vac 50/60 Hz; 190 250 Vac 5016O Hz: 8 VA maximum MECHANICAL Front Panel Controls: THRESHOLD -40 dB to +20 dB: RELEASE 0.05 s to 5 s/20 dB: RANGE O dB tO -60 dB; OUTPUT -15 dB to +15 dB Front Panel Switches: pk/avg/gate DET (detector); int/ds-fm/ext DET (source); limit/out/exp MODE LINK (connects control circuitry of both channels for stereo operation) POWER On, Off (as indicated by power on LED) Metering: 8 LED gain reduction meter I LED clip warning indicator Rear Panel Adjustments: Channel 1 and Channel 2 CNTL. REJ. trimmer potentiometer accessi- ble through rear panel removes dc offset from the line driver stages Rear Panel Connectors: V+ diameter,3 conductorjacks; re- quire Switchcraft f260 or equivalent mating plugs. A transformer balanc- ed output/XlR connector option is available at additional cost. 1.3 INTRODUCTION TO DYNAMICS PROCESSING A. DYNAMITE is a powerful tool for the processing of audio signal dynamics. Its fullest potential may be realized only after the user has acquainted himself with its operation, and become familiar with its controls. To this end, it is recommended that the user take time to carefully read over the information contained herein. Dynamics processing is simply what the name implies- manipulating the dynamics of an audio signal. The two processes with which we are most familiar are COMPRESSION or LIMITING, and EXPANSION. They are essentially opposite functions. Compression or Iimiting involves automatically lowering the signal gain as the signal increases, thereby reducing, restricting or limiting the dynamic range. Expansion results when the signal gain is lowered as the signal level decreases, thereby extending the dynamic range. The degree to which signal gain is altered in response to a change in signal level is called the RATIO. Ratio, be it limiting ratio, compression ratio, or expansion ratio, is expressed as the ratio between a signal level change at the input of the device, vs the signal level change at the device output. In a linear amplifier, the relationship of input change to output change is direct; thus the ratio is stated as l:1.a ldB increase in input signal level produces a ldB increase in output level. A perfect limiter has a ratio of infinity:1. Thus, during limiting, an infinite increase o1 input signal level is required to produce a ldB increase in output level. Accordingly, the output is maintained at a constant clamped output level, and a leveled output results whenever the device is limiting. Limiter-like devices whose ratio is less than 8:l are nornrally termed compressors. For example, a device having a 2:i raiit., will output a ldB increase in level for each 2dB level increase al the input. Compressors are seldom used in modern signal prcrces- sing (except in compress/expand noise reduction systems .n,t canned music systems). Some manufacturers offer co)n- pressor/limiters wherein the compression feature is includecl as a watered down form of limiting, to be used in situations wherc the use of full limiting results in audible degradations to rhr: dynamics. The result, of course, is a less than optimum control ol signal dynamics. . . a compromise. In the DYNAMITE structure. we have chosen to deal with the detec- tor mechanism, which can cause dynamics degradation, in order to allow full control while maintaining dynamic integrity. Output Noise ty gain, RadioFans.CN 收音机爱 好者资料库 Looking at the expansion end of the spectrum, let us visualize envelope, but not the actual cycles unfortunately this cannot be a device having a ratio of 1:2. This means a ros irrpuir.r .nung. d; i;tice, as a suddenly occurring energy burst in the will cause a 2dB output change. This action t.nir*to ,*t . toria signal source ,nurt b. dealt with quickly if any usable form of sounds louder, and soft rourrd, softer. For tt. raie oinot over- ovnu,ni.r manipulation is to be realized Thus we have the loading the systems *hi;h i;lr; an expander,-expansion in a ,.q,rit.*.ni irtut ttt. gain controlling mechanism respond device like Dyna-Irite is normally kept in tt.-region*oimaking ,.rliiurv tupidly to a suddenly applied burst of input signal soft sounds softer, or downward expansion. wt,.riun ouiput gaii (suctr as ttreueat of a drum, eti)-ihis parameter is called the control is included in tt.-J.ui., though, it becomes somewhat device attack. arbitrary as to whether the expander is ,downward, or ,bi-direc- once a burst of input signal has caused the device gain to tional,. To clarify, assume the output gain control were set for a q.,ittv.trurrge (downward iicompressing or limiting upward if nominal gain of + l0dB, and expansion action were introduced. expanding;, we must prevent further instantaneous response In such a setup, the louder signals could be made to appear at a-pt.r?in. eain from changing with every minute peak or dip the output rOdB higher than thi input signal r.u.ilu, proar.irg of ihe wavefor-m itself. This ntracking would effectively cause ,.upward expansion,. n using such a structure, however, thi waveform distortion Hence a releise structure is required user would have to insure that the equipmeni following the ru.tt tttui return gain changes (gain changes in the absence. of expander were capable oi accepting rh. ln.r.ur.i rlprlJigr input signal) are relatively slow. This is always a compromlse levelwithout overloading. witt, ceitain sorts of program material, it is desirable to restore The relatively mild l:2 expansion ratio is useful for generally ttt.-a*rc. quickly; yei, if-the gain restoration becomes too fast increasing the dynamic range of a signal .ro*.f, -uri ior ir- distortion results. A similar compromise exists with respect to creasing the apparent-uoiui,. difference between itr. aerir.o the attack structure. Both situations will be discussed in greater signal and the background noise which accompanies it.For detaillateron situationswhereamoredefinedrelationshipof sfiiaiunOnoi,ei . N; we come to the question: At what point in the signal desired, the ratio .uy b. increased to L:10 iu.vrJ. s.tr level spectrum do these gain changes occur? This point is called expansion ratios are normally cailed noise guiing-ratior. rne THRE-SHOLD. Let us take the example of an infinity:l ratio srightest detected signal ,gates, the expande, t, ,?ir. gi.l r, limiter. Let us say that a + 4dBv input signal threshold is selected while noise levels do not. while such high ratios may all,ow more unJ tnut the device has a nominai gain of OdB or unity with effective reduction of unwanted noise signals, ulooi deal of car.e r.rr pu*-.,ers, the device will act is a normal unity gain ampli- is dictated in assuring rhe THRESHoLD or .rriii.r,ing point i, il;l;n8; the input signal is lower in level than the specified placed such that the r.* r.1 portions of th.e desireisignal are *+ogu tliieshold. Sin. ittt device is doing nothing urider not eliminated along with the noise. with *iJ. 1g./rr.* these conditions, its ratio is l:1. Now let us assume that an input atracking signals such as voice, strings and ttr. tit., itrJur. or uu.ri -.uru.ing + l0dBv suddenly appears The limiter will gating ratios becomes ;rly ;t;iUt., u, tf,1 iniiiuf parts of attack in response to this over-threshold signal reducing its signal waveforms are in the noise spectrum, and thus cannot be gi; ;- - oog, ittu, causing the signal burst to exit the limiter at effectively separated. Attempts to use gating.ru,io, on such signal ;Aii; Haa ihe input sigial burit been + l4dBv l0dB of gain sources will often result in an audible .,.ti.tingll, a, the nornially reduction would have beei caused to achieve the desired + 4dBv smooth attack of the tflt Uttptly switchid on output clamp Thus, high ratio expansion is usualry used only on percussive -ttotto*ingthe input burst, the release circuitry would gently type instrumentr-tnoJ. *r,ich inherenily have a iefinld attack. return the gain back to unity For other instruments, noise control is more effectively per- - -in.a.iinitionof rHREsHoLD,whenappliedtoalimiteror formed using rower .*pln,io-n uiios suctr as t:z :*t*:i:i:m ffi:;h,fT:Jt:TIli*Htfli:iil; B. Threshold/Attack/Release. It should be clarified that accordingtoitsratio audio dynamics processing devices cannot operate instan- For in expander or noise gate structure, the situation is taneously, as do conventional amplifiers. If such were the case, r.u.tr.a. In these devices the threshold is the signal level above the processing a.ui *ouiJ u.o-. a non-linear amplifier which *ti.tr tt. device does nothing, and below which it performs gain actually distorts the signal waveform. Obviou-sly, we do not want reduction according to its ratio waveform modification in an audio system. wtrat is desired is to it should be noted that in both examples the attack is in alter the envelope, rather than the individuar lvcr.s themselves. ,.rpoor.,o increasing sig.nal levels, while the release is in response Ideally, for minimum signal distortion, th.e gain changes would l i.*irg signali Figures 1A and lB graphically illustrate occur very slowly, r.frivirgitr. geneial siape of the signal thesebasicparameters ?* GAIN REI,EASE TTIBISIOLI) INPTJT SIGIAL OUTPUT SICNAL 3-.- C ngmRsr FIGURE 1A LIMTING 4 FGURE 1B EXPANDING ATTACK C. Detector Circuits. Several alternatives are available to the circuit designer in structuring the detector mechanism (that mechanism which measures the level fluctuations of the input signal). At first glance, this may sound easy.just measure the voltage excursions. In fact, the graphics of Figure lA illustrate a circuit which does just that. Such a detector is called a peak detector, in that it measures the peak excursions, of either polarity, of the input signal. Peak detection was the backbone of early limiters which were designed for broadcast and disc cutting chains. In these peak level critical systems, the prime requirement was to prevent overloading the subsequent stages. These detectors were required to act nearly instantaneously, on the order of l0prs to lOops, to form an absolute electrical clamp. Fast peak detection still remains the only viable method of controlling signal level to such inputs. Unfortunately, the electrical peak value of a music waveform has little to do with how loud the sound is perceived by the human ear, due to the varying WAVEFORM COMPLEXITIES. To illustrate this point, Figure 2 plots the relative electrical and audible values for two typical music waveforms, one relatively simple, and one moderately complex. As can be seen, although the two waveforms appear at the same level of audible loudness, they exhibit completely different electrical peak values. I