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Inovonics 261 Скачать руководство пользователя страница 27

23

a cross-coupled feedback network that make it perform more like a

transformer-coupled output than the more common antiphase op-

amp circuits.
With the 261 delivering a +4 output, for example, +4dBu will be

measured

between

pins 2 and 3 of the

LEFT ANALOG LINE OUT

con-

nector. If the voltmeter instead measures either output pin with a

ground

reference, however, the reading will be 6dB low, or 2dBu.

But grounding either pin 2 or pin 3 will force the other side of the

output back up to +4dBu. A truly balanced output!

DIGITAL INPUTS AND OUTPUTS

The AES/EBU digital input of the Model 261 is transformer-isolated

by T2. Digital audio is fed to the DSP board on pin 36 of J9.
On the DSP board, digital audio is delivered directly to pin 23 of the

DSP support chip, IC1, where it is formatted for processing by the

DSP, IC2.
IC1 also converts raw processed data back into the AES/EBU for-

mat, which is delivered to the main board on pin 35 of J9. The vari-

ous sections of IC6 deliver a quasi-balanced AES/EBU digital output

to the connector of the same name on the rear panel of the 261.

ALARM TALLIES

The DSP chip, IC2, directly drives three transistors, Q1, Q2 and Q3.

The open collectors of these transistors provide a solid state clo-

sure to ground for the three program signal fault alarms. +5V is de-

livered to the terminal strip as well, and is current-limited by R6.

POWER SUPPLY

The power transformer, on the main circuit board, has dual primary

windings that may be switched in parallel or in series for 115V or

230V AC mains. Bridge rectifier CR1 delivers raw DC to three

switching regulators, IC1, IC2 and IC3, pro3.3V, +12V and

12V, respectively. Linear regulators IC4 and IC5 reduce the ±12V

to ±5V for analog ICs on the DSP board.

THE DSP BOARD

There s really not much to say about the DSP board, beyond the

analog buffer amplifiers already described.
The ADAV803 DSP support chip, IC1, has already been credited

with providing all A/D, D/A and AES/EBU formatting functions. In

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Содержание 261

Страница 1: ...RATING AND MAINTENANCE INSTRUCTION MANUAL MODEL 261 DIGITAL UTILITY AUDIO PROCESSOR interstage Phistersvej 31 2900 Hellerup Danmark Telefon 3946 0000 fax 3946 0040 www interstage dk pro audio with a smile ...

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Страница 3: ..._______________ Warranty Card Mailed o OPERATING AND MAINTENANCE INSTRUCTION MANUAL MODEL 261 DIGITAL UTILITY AUDIO PROCESSOR Rev 2 March 2008 HF Limiter Addition 1305 Fair Avenue Santa Cruz CA 95060 TEL 831 458 0552 FAX 831 458 0554 Visit our Website www inovon com ...

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Страница 5: ...nnections ALARM TALLY OUTPUTS 9 SELF CALIBRATION UTILITY 10 Section III SETUP AND OPERATION NAVIGATING THE MENU AND SELECTION OPTIONS 11 Front Panel Buttons Panel Lockout Switch INITIAL POWER ON AND SETUP 11 Splash Screen Alarms Analog Digital Inputs Output Sampling Rate SETTING LEVELS 13 Input Gain Adjustment Analog Input Gain Studio Levels Analog Input Gain Semi Pro Equipment Digital Input Gain ...

Страница 6: ... Component Annotation ANALOG INPUTS AND OUTPUTS 22 Analog Line Input Analog Line Output DIGITAL INPUTS AND OUTPUTS 23 ALARM TALLIES 23 POWER SUPPLY 23 THE DSP BOARD 23 PROGRAM AND SETTINGS MEMORY 24 Section V APPENDIX EXPLANATION OF PARTS LISTINGS 26 PARTS LISTINGS 24 SOURCES FOR COMPONENT PARTS 28 SCHEMATIC DIAGRAMS 29 INOVONICS WARRANTY INSIDE BACK COVER ...

Страница 7: ...ontrolled by navigating a menu with a simple series of pushbuttons A rear panel switch may be used to lock out the front panel selector buttons to protect processor setup Features Leading features of the Model 261 include Gain riding AGC erases long term level variations in the input program source Look ahead peak limiting provides absolute ceiling peak control without flat topped clipping Indepen...

Страница 8: ...balanced XLR out puts deliver nominal program line levels between 10dBm and 10dBm AGC Function Unobtrusive peak and average weighted correction for long term input level variations 15dB cap ture range Compressor Limiter The look ahead design has pro gram controlled attack and release timing optimized for unobtrusive operation The average level com pression feature incorporates addi tional gain wit...

Страница 9: ...plified Block Diagram of the Model 261 shown as an analog equivalent of the digital audio processing ar chitecture A full set of schematic diagrams appears in the Appen dix Section V Figure 1 Block Diagram Model 261 Digital Utility Processor ...

Страница 10: ...t registration also ensures that the user will automatically receive any service or modification instructions MOUNTING Rack Requirement The Model 261 mounts in a standard 19 inch equipment rack and requires only 1 inches 1U of vertical rack space We recommend screws with plastic washers to protect the painted finish around the mounting holes Heat Dissipation Consuming less power than a fish tank a...

Страница 11: ... felt pen Power Cord The detachable IEC type power cord supplied with the 261 is fitted with a North American standard male plug The individual cord conductors may be color coded in either of two ways regardless of the shipping destination 1 In accordance with US standards BLACK AC HOT WHITE AC NEUTRAL GREEN EARTH GROUND 2 To European CEE standards BROWN AC HOT BLUE AC NEUTRAL GRN YEL EARTH GROUND...

Страница 12: ...o Pin 3 Analog Input Gain Range The 261 can accommodate line level program inputs with a nominal Zero VU value anywhere between 25dBu and 10dBu A set of jumpers beneath the top cover optimizes the range of the menu accessed INPUT GAIN adjustment and helps to avoid A D converter headroom issues As shipped the Model 261 is jumpered for line levels in the 4dBm range common to most audio consoles and ...

Страница 13: ...sistive source impedance of 200 ohms The nominal 0VU output line level may be adjusted between 15dBu and 10dBu with the front panel menu and buttons See Page 13 If the 261 is connected to feed single ended unbalanced equipment connect the center conductor of the shielded interconnect lead to Pin 2 of the XLR connector and the shield both to Pin 1 and to Pin 3 ALARM TALLY OUTPUTS The 261 has rear p...

Страница 14: ...ine basis However if either the DSP board or the plug in EEPROM on the main board are replaced for a firm ware upgrade for example the self calibration routine will start with the next power up Alternatively self calibration can be forced by holding down all four menu navigation buttons while power is turned on Whether the routine self initiates or is forced follow instructions that will appear on...

Страница 15: ...owing a power interruption Panel Lockout Switch Because the t and u buttons make actual and audible changes in the operation of the processor a switch is provided to lock these buttons out This switch is located on the rear panel and is labeled FRONT PANEL with UNLOCK and LOCKED positions When the switch is in the LOCKED position t and u buttons do not function although the menu may still be scrol...

Страница 16: ...e fault condition to be cleared Analog Digital Inputs Use the p and q buttons to cycle to the INPUT and OUTPUT screen With the w cursor set as shown below use t and u buttons to se lect either the ANALOG input or the DIGITAL input whichever is the one that will be used Output Sampling Rate Regardless of the input mode selection both the analog and digital outputs are simultaneously available When ...

Страница 17: ...larly a 8dBm program line would require a 8dB setting Analog Input Gain Semi Pro Equipment Disco mixers consumer CD players and other gear of that genre has typical line levels in the 300mV range or about 10dBu When con necting the ANALOG INPUT s to this equipment observe the con nection instructions on Page 8 and set the circuit board input gain jumpers in the 10 position as described on the same...

Страница 18: ...satisfactory for both modes which are available simultaneously Analog Output Level With reference to the maximum fully limited ceiling output of the peak limiter an OUTPUT gain setting of 0dB will yield a balanced analog line output of 0dBu Thus to match a nominal 4dBm pro gram line OUTPUT gain would be set to 4dB To match typical con sumer equipment line levels OUTPUT gain would be set somewhere ...

Страница 19: ...her hand is slow and unobtrusive AGC is enabled by scrolling with the q button to the next screen With the w cursor positioned as shown above t and u may be used to toggle the AGC among its three modes OFF NORMAL and FAST Gating Defined and the GATE Indicators An AGC or other processing function is said to be gated when gain is held or locked during brief pauses in the program This prevents backgr...

Страница 20: ...situations are better served with non symmetrical AGC action Sportscasting and classical music are two examples In both in stances low level events such as crowd noises and pianissimo pas sages are legitimate parts of the program These may well be of a sufficient level to open the AGC gate but they do not want to be brought slowly to full modulation by the AGC For this reason a cap or ceiling valu...

Страница 21: ...t in our products this tends to be quite near the output final limited ceiling value leaving all dynamics of the program untouched before a certain critical amplitude at which all action starts to take place The Compression Platform Beginning with the introduction of our first audio dynamics proces sor for broadcasting in 1974 Inovonics has utilized the floating platform principle of dynamic range...

Страница 22: ...its optimum range controlling only the program peaks in an unobtrusive manner In the limit only mode limiter action is not gated Note the solid block at 0dB on the COMPRESSION LIMITING scale Also note that AGC has been enabled in this case and that the gate is closed Peak reduction will be shown on the upper bargraph with a peak hold segment showing the highest recent value of gain reduction as il...

Страница 23: ...d by a static 6dB At the same time this added gain is subtracted out by forcing the compression platform to a 6dB resting point Compression is gated the same as the AGC and in the illustration above the gate is closed Compression will seek its 6dB resting value just as the AGC seeks 0dB As the input program signal has been given additional static gain the comparative loudness of the program materi...

Страница 24: ...ith the t and u select buttons the HF limiter can be set to pro tect either the 50µs or 75µs pre emphasis transmission curves When either characteristic chosen another programming option be comes available Flat or Pre Emphasized Output With the HF limiter engaged the output of the 261 may be set to have either a flat or a pre emphasized output characteristic This is set by scrolling down q to OUTP...

Страница 25: ...lue at frequencies above the pre emphasis turnover point Use this setting only if pre emphasis is turned off in the stereo gen or exciter CAUTION Be aware that double pre emphasis will result if the 261 is set as shown above and the stereo generator or FM exciter imparts transmission pre emphasis as well This is a condition to be avoided like the proverbial plague ...

Страница 26: ...s is one of the great benefits of the rapid progress in our in dustry ANALOG INPUTS AND OUTPUTS Analog Line Input Referring to the left program channel which is identical to the right IC11A and IC11B are unity gain buffers for the differential balanced analog program line input The attenuator associated with the circuit board gain range jumper JP2 delivers a balanced drive to pins 31 and 32 of the...

Страница 27: ...hich is delivered to the main board on pin 35 of J9 The vari ous sections of IC6 deliver a quasi balanced AES EBU digital output to the connector of the same name on the rear panel of the 261 ALARM TALLIES The DSP chip IC2 directly drives three transistors Q1 Q2 and Q3 The open collectors of these transistors provide a solid state clo sure to ground for the three program signal fault alarms 5V is ...

Страница 28: ...a MOSFET Q1 and coil L1 PROGRAM AND SETTINGS MEMORY IC12 on the main board is a serial EEPROM memory chip At power up the contents of this memory are loaded into the DSP This includes the processing algorithms and all user settings which are loaded back into this chip as they are made IC12 provides an easy and relatively inexpensive means of issuing updates for the 261 Replacing this plug in IC am...

Страница 29: ...25 Section V APPENDIX This section of the Model 261 Manual con tains Parts Listings Schematic Diagrams and an explanation of Inovonics Generous and Liberal Warranty Policy ...

Страница 30: ...ble Should you need to order part that is not listed here call write fax or e mail the factory with a brief description of what it is that you need We ll then do our very best to figure out what to send you maybe a surprise PARTS LISTINGS C1 2 Capacitor Y class Ceramic Disc 0047µF 440VAC Mu rata Erie DE7150 F 472M VA1 KC C3 Capacitor Electrolytic radial leads 2200µF 35V Digi Key P7 466 ND C4 6 8 C...

Страница 31: ... 06 J3 5 6 Connector XLR Male Neutrik NC3MAH J4 7 8 Connector XLR Female Neutrik NC3FAH2 0 J9 10 11 501 Connector Dual Row Breakapart Header as required JP1 2 Connector Single Row Breakapart Header as required Shorting Shunt for 0 1 inch header strips open L1 3 Inductor 78uH 0 82A Digi Key TE2097 ND Q1 3 Transistor NPN open 2N3904 Except at noted by reference designation all resistors used in the ...

Страница 32: ...e for your replacement compo nent needs The electronic component distributors listed below have proven themselves reputable suppliers for small quantities of component parts for broadcasters and for other commercial or professional us ers With all due diligence please avoid the temptation to use cross referenced hobbyist or TV VCR Repair Shop direct replacement ha parts A majority of the ICs capac...

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Страница 37: ... altered III TERMS OF WARRANTY Inovonics Inc products are warranted to be free from defects in materials and workmanship A Any discrepancies noted within ONE YEAR of the date of deliv ery will be repaired free of charge or the equipment will be re placed with a new or remanufactured product at Inovonics op tion B Parts and labor for factory repair required after the one year Warranty period will b...

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