ORBAN 2200 Manual Section 3 电路图.pdf

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1、Section 3 Operation pagecontents 3-32200 Controls and Meters 3-5Introduction to Processing 3-7About the Processing Structures 3-7Factory Programming Presets 3-9Customizing the 2200s Two-Band Sound 3-11Two-Band Processing Control Details 3-19Customizing The Protection Limiter Structure Sound 3-19Prot

2、ection/Limiting Control Details 3-212200 Screen Displays Caution The installation and servicing instructions in this manual are for use by qualified personnel only. To avoid electric shock do not perform any servicing other than that contained in the Operating Instructions unless you are qualified t

3、o do so. Refer all servicing to qualified service personnel. OPTIMOD-FM 2200OPERATION 3-1 RadioFans.CN 收音机爱 好者资料库 page 3-2 OPERATION OPTIMOD-FM 2200 RadioFans.CN 收音机爱 好者资料库 2200 Controls and Meters 2200 Front Panel Screen Display labels the four soft key buttons and provides control setting informa-

4、 tion. Screen Saver feature: The screen has a built-in screen saver that turns off the backlight after approximately one hour. The screen turns back on when any front panel control is touched. Note that buttons dont perform their normal function when the screen is blank. Similarly, the control knobs

5、 first turn is not read, until it stops for a second or so. Contrast Button adjusts the optimum viewing angle of the screen display. Press this button to cycle through four contrast settings for the screen display. Four Soft Key Buttons provide access to all 2200 functions and controls. The function

6、s of the buttons change with each screen according to the labels at the bottom of each screen. Push a button: To select options (always identified on the screen by all-capital-letter words surrounded by left and right vertical bars), press the button directly below the option. To change a parameter

7、setting (always identified by lower-case letters or numerals), hold down the button directly below the parameter setting, turn the control knob to scroll through choices, and release the button to set the parameter. Control Knob is used for changing data in one of three methods. To scroll through su

8、bmenu choices: Presets (on Recall Preset screen), FULL CONTROL parameters (on Modify Processing FULL CONTROL screen) and 8 Remote Interfaces (on System Setup REMOTE INTERFACE screen). To change a parameter setting, by simultaneously holding down a soft key. The parameters being changed take effect i

9、mmediately, except for the following system level controls: MODE (on test screen), MODE (on Stereo Encoder screen), INPUT, AO PRE-E, DO PRE-E, DO RATE, DO SYNC and XTLK TEST. The setting for these controls do not take effect until the soft key is released. To adjust the LESS-MORE control. Adjusting

10、this control changes the sound immediately. Escape Button returns the user to the previous screen; pressing this button repeatedly will always return you to main screen, which shows the on-air preset name. Recall Preset Button brings up a screen that displays the current on-air preset and next prese

11、t (which can be changed by turning the control knob). To put a different preset on-air, turn the control knob to find the preset desired, then press the RECALL NEXT soft key. When the buttons yellow LED is lit, the Recall Preset screen is displayed. OPTIMOD-FM 2200OPERATION 3-3 RadioFans.CN 收音机爱 好者资

12、料库 Modify Processing Button brings up a screen to modify parameters for the current on-air preset. For Two-Band presets: LESS-MORE, EQ and FULL CONTROL. For the Protection preset, DRIVE and 30HzHPF. When the buttons yellow LED is lit, the Modify Processing screen (or one of its submenus) is displaye

13、d. System Setup Button brings up a screen to modify system settings (such as I/O levels). There are four System Setup submenus: I/O CALIB, STEREO ENCODER, RE- MOTE INTERFACE, TEST. When the buttons yellow LED is lit, the System Setup screen (or one of its submenus) is displayed. HF Limiting LEDs lig

14、ht when the high-frequency content of audio is being limited by the very fast high-frequency limiters. These LEDs indicate when greater than 0.5dB HF limiting is occurring. Gated LED indicates gate activity, lighting when the input audio falls below the threshold set by the gate threshold control (M

15、odify Processing screen GATE THRS control). When this happens, the compressors recovery time is drastically slowed to prevent noise rush-up during low-level passages. Composite Meter is a 10-segment bargraph showing the stereo encoders composite output level before the composite level controls. Func

16、tion Button selects which of three functions are displayed in the Function meters: Enhance, L/R Input or L/R Output. Function LEDs indicate which function is currently displayed by the Function meters: Enhance, L/R Input or L/R Output. Press the Function button to toggle between the three functions.

17、 Function Meter indicates level of Enhance, L/R Channel Input or Output, as selected with Function button. The meters operate over a 27dB to 0dB range. Input meters are referenced to clip level. Output meters are referenced to 100% modulation level. HF Enhance meter shows the active amount of enhanc

18、ement activity. Since the HF Enhancement is program-dependent, it will vary with source material and the HF parameter. Note: HF Enhance is displayed only on the left-hand meter, below “HF.” Stereo Encoder Screwdriver-Adjustable Controls Orban supplies a special green-handled flat-blade screwdriver (

19、Xcelite R3323) to adjust the stereo encoder controls. Comp 1 sets the output level of Composite Output 1. Comp 2 sets the output level of Composite Output 2. 3-4 OPERATION OPTIMOD-FM 2200 Introduction to Processing Some Audio Processing Concepts Loudness is increased by reducing the peak-to-average

20、ratio of the audio. If peaks are reduced, the average level can be increased within the permitted modulation limits. The effectiveness with which this can be accomplished without introducing objectionable side effects (such as clipping distortion) is the single best measure of audio processing effec

21、tive- ness. Compression reduces the difference in level between the soft and loud sounds to make more efficient use of permitted peak level limits, resulting in a subjective increase in the loudness of soft sounds. It cannot make loud sounds seem louder. Compression reduces dynamic range relatively

22、slowly in a manner similar to riding the gain: limiting and clipping, on the other hand, reduce the short-term peak-to-average ratio of the audio. Limiting increases audio density. Increasing density can make loud sounds seem louder, but can also result in an unattractive busier, flatter, or denser

23、sound. It is important to be aware of the many negative subjective side effects of excessive density when setting controls that affect the density of the processed sound. Clipping sharp peaks does not produce any audible side effects when done moderately. Excessive clipping will be perceived as audi

24、ble distortion. Distortion in Processing In a competently-designed processor, distortion occurs only when the processor is clipping peaks to prevent the audio from exceeding the peak modulation limits of the transmission channel. The less clipping that occurs, the less likely that the listener will

25、hear distortion. However, to reduce clipping, you must decrease the drive level to the clipper, which causes the average level (and thus, the loudness) to decrease proportionally. The FM pre-emphasis curve introduces further complications. Pre-emphasis boosts the treble at 6dB/octave starting at 2.1

26、kHz (for 75s countries) or 3.2kHz (for 50s countries). This reduces the headroom available at high frequencies, and makes it difficult to achieve a bright sound. This is because bright sound requires considerable high-frequency power to appear at the output of the receivers de-emphasis filter, and t

27、hus requires a very large amount of high-frequency power to be transmitted so that a sufficient amount will survive the de-emphasis process. Without very artful processing, the pre-emphasis will radically increase the level of the peaks and force you to decrease the average level proportionally. Orb

28、ans high-frequency limiting and distortion-canceling clipping systems greatly ease this trade-off, but cannot entirely eliminate it. Therefore, you can only increase brightness by reducing average modulation (loudness) unless you accept the increased distortion caused by driving the final clippers h

29、arder. OPTIMOD-FM 2200OPERATION 3-5 Loudness, Brightness and Distortion. In processing, there is a direct trade-off between loudness, brightness, and distortion. You can improve one only at the expense of one or both of the other two. Thanks to Orbans psychoacoustically-optimized designs, this is le

30、ss true of Orban processors than of any others. Nevertheless, all intelligent processor designers must acknowledge and work within the laws of physics as they apply to this trade-off. Perhaps the most difficult part of adjusting a processor is determining the best trade-off for a given situation. We

31、 feel that it is usually wiser to give up ultimate loudness to achieve brightness and low distortion. A listener can compensate for loudness by simply adjusting the volume control. But there is nothing the listener can do to make an excessively-clipped signal sound clean again, or to undo the effect

32、s of excessive high-frequency limiting. If processing for high quality is done carefully, the sound will also be excellent on small radios. Although such a signal might fall slightly short of ultimate loudness, it will tend to compensate with an openness, depth, and punch (even on small radios) that

33、 cannot be obtained when the signal is excessively squashed. If women form a significant portion of the stations audience, bear in mind that women are more sensitive to distortion and listening fatigue than men. In any format requiring long- term listening to achieve market share, great care should

34、be taken not to alienate women by excessive stridency, harshness, or distortion. OPTIMOD-FM from Bach to rock OPTIMOD-FM can be adjusted so that the output sounds as close as possible to the input at all times (using the Protection Limiter Structure), or so that it sounds open but more uniform in fr

35、equency balance (and often more dramatic) than the input (using the Two-Band Structure). The loudness/brightness/distortion trade-off explained above applies to any of these setups. You will achieve best results if Engineering, Programming, and Management go out of their way to communicate and coope

36、rate with each other. It is important that Engineering understand the sound that Programming desires, and that Management fully understand the trade-offs involved in optimizing one parameter (such as loudness) at the expense of others (such as brightness, distortion, or excessive density). Never los

37、e sight of the fact that, while the listener can easily control loudness, he or she cannot undo excessive high-frequency limiting or make a distorted signal clean again. If such excessive processing is permitted to audibly degrade the sound of the original program material, the signal is irrevocably

38、 contaminated and the original quality can never be recovered. 3-6 OPERATION OPTIMOD-FM 2200 About the Processing Structures In the 2200, a processing structure is a program that operates as a complete audio processing system. Only one processing structure can be active at a time. There are two proc

39、essing structures in the 2200: Two-Band Protection/Limiting Unlike an analog system, where creating a complete processing system involves physically wiring its various components together, the 2200 realizes all of its processing structures as a series of high-speed mathematical computations made by

40、Digital Signal Processing (DSP) integrated circuit chips. So the 2200 can be changed from one structure to another by loading new software from high-speed semiconductor memory within the 2200. Factory Programming Presets Factory Presets are our “recommended settings” for various program formats. The

41、se presets were designed by our experienced engineers as good starting points for the program format. In many cases, the sound of the factory preset will suit your needs without the need for further adjustment. There are eight factory presets: Classical-Protect 2B General Purpose Talk Music-Light Mu

42、sic-Medium Music-Heavy Music+Bass Medium Music+Bass Heavy Classical-Protect produces a very clean, open sound that is ideal for stations whose success depends on attracting and holding audiences for very long periods of time. It uses the Protection/Limiting structure. All other presets use the Two-B

43、and structure. 2B General Purpose provides an average amount of processing; Talk provides processing for Talk format stations that primarily feature news, call-in shows, interviews, and other voice material. TALK keeps the levels of announcers and guests consistent, and keeps a proper balance betwee

44、n voice and commercials. Music-Light produces a very open, unprocessed sound. This is a sound that is easily listenable for many hours without fatiguing listeners. OPTIMOD-FM 2200OPERATION 3-7 Music-Medium provides processing that is between Music-Light and Music-Heavy. This is a good choice for man

45、y stations. Music-Heavy provides aggressive processing for stations that want to maximize on-air loudness, and that do not assume that a listener will listen to the station for hours at a time. Music+Bass Medium produces a very punchy, clean, open sound. Music+Bass Heavy provides aggressive processi

46、ng with additional bass punch. Start with one of these presets. Spend some time listening critically to your on-air sound. Listen to a wide range of program material typical of your format, and listen on several types of radios (not just on your studio monitors). Then, if you wish, customize your so

47、und using LESS-MORE, EQ and FULL CONTROL. To recall a preset: Press Recall Preset Button. Turn the control knob to scroll through preset list and stop when you find a desired preset. Press RECALL NEXT soft key button. It is normal for the audio to mute for about a second when switching between a pre

48、set based on the Two-Band structure and a preset based on the Protection/Limiting structure. This gives the 2200 time to download the appropriate code to its DSP chips. 3-8 OPERATION OPTIMOD-FM 2200 Customizing the 2200s Two-Band Sound The subjective setup controls on the 2200 give you the flexibili

49、ty to customize your stations sound. But, as with any audio processing system, proper adjustment of these controls consists of balancing the trade-offs between loudness, density, brightness, and audible distortion. When you start with one of our Two-Band factory presets, there are three levels of subjective adjustment available to you to let you customize the factory preset to your requirements: LESS-MORE EQ FULL CONTROL. LESS-MORE After selecting a factory preset, LESS-MORE is the next level of adjustment. As you go from less to more, the air sound will become louder, but (a