User manual APOGEE BIG BEN

[. . . ] 192k Master Digital Clock User's Guide v1. 0 - June 2003 192k Master Digital Clock User's Guide v1. 0 - June 2003 BIG BEN ­ User's Guide Warnings FCC warning This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to Part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference when operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference, in which case the user will be required to take whatever measures necessary to correct the interference at his own expense. Copyright Notice The Apogee BIG BEN is a computer-based device, and as such contains and uses software in ROMs. [. . . ] The following sources are available: When video has been selected as the clock source, allow Big Ben approximately 30 seconds to achieve the best lock. · INT ­ Big Ben's clock outputs are derived from an internal clock · · · · · · · frequency generator. CLOCK SOURCE must be set to INTernal to set the PULL UP/DOWN parameter to VSO, AES1 ­ clock and digital audio outputs are derived from the AES1 input. If AES is set to DOUBLE, both AES1 and AES2 will light. AES 2 ­ clock and digital audio outputs are derived from the AES2 input. S/P COAX ­ clock and digital audio outputs are derived from the S/PDIF coaxial input. OPTICAL - clock and digital audio outputs are derived from the Optical input. OPTION - clock and digital audio outputs are derived from the Option Card input. This selection is only available when an Option Card is installed. WC - clock outputs are derived from the Video/Word Clock input when a valid word clock signal has been connected. VIDEO - clock outputs are derived from the Video/Word Clock input when a valid video signal has been connected. The video format (PAL, NTSC or B&W) will be automatically detected. APOGEE ELECTRONICS 5 BIG BEN ­ User's Guide Navigating the Front Panel - continued 4 5 The better the input reference signal, the smaller the phase differences between that input and Big Ben's ultra-stable output . If these phase differences are less than 1 degree (as depicted in FIGURE 1), the NARROW and WIDE LEDs light. If, on the other hand, these phase differences increase to a point where a loss of lock may occur (as depicted in FIGURE 2), the Narrow LED will extinguish, leaving only the WIDE LED lit. Though Big Ben's output will remain remarkably stable, loss of NARROW lock indicates a stability problem with the input reference signal, caused by excessive jitter or electrical failure. 4) SAMPLE RATE ­ When CLOCK SOURCE is set to INTernal or VIDEO, SAMPLE RATE displays the frequency of the internally generated clock, and may be set to a frequency of 44. 1 -192 kHz. When CLOCK SOURCE is set to any other value (AES1, AES2, S/P COAX, OPTICAL, OPTION or WC), SAMPLE RATE displays the frequency detected at the selected input. 5) Lock Indication LEDs ­ Big Ben's lock status to the selected CLOCK SOURCE is indicated with a group of 5 LEDs; the following states are indicated: · Blinking Green Arrow ­ Big Ben is not locked to the selected CLOCK SOURCE. · Solid Green Arrow + "WIDE LOCK" displayed ­ Big Ben is locked · to the selected CLOCK SOURCE, but the quality of the input signal is questionable. Solid Green Arrow + Blue Dot + "NARROW LOCK" displayed ­ Big Ben has achieved the most precise lock possible. Blinking Green Arrow + Blue LED solidly lit ­ Big Ben is no longer locked to the selected CLOCK SOURCE (indicated by the Blinking Green Arrow) but has entered Surelock mode and is transmitting a stable clock nevertheless (indicated by the solidly lit Blue LED. · FIGURE 1 FIGURE 2 Note that Apogee's use of Wide and Narrow terminology differs from that of other manufacturers, who use "narrow" to designate a clock reference running precisely at standard rates, and "wide" to designate a clock reference running at any varispeed rate. 6 APOGEE ELECTRONICS BIG BEN ­ User's Guide Navigating the Front Panel - continued 6 7 6) OPTICAL ­ This parameter determines the format of the Optical Input/Output connectors. 7) AES - This parameter determines the format of the AES Input/ Output connectors. Valid settings of the OPTICAL and AES parameters are determined by the SAMPLE RATE as depicted in FIGURE 3 below; Please see the section of this manual entitled "About Digital Audio Formats and Format Conversion" for a more detailed explanation of Big Ben's digital functionality. 192/176. 4 S/PDIF ADAT S/MUX 2 S/MUX 4 AES Single AES Double valid x x valid valid valid 96/88. 2 valid x valid x valid valid 48/44. 1 valid valid x x valid x FIGURE 3 APOGEE ELECTRONICS 7 BIG BEN ­ User's Guide Navigating the Front Panel - continued 8 9 In VSO mode: due to the limitations of a 4 digit display, only one of the three units of measurement can be displayed accurately; display values for the remaining two units are approximated. Whichever unit of measurement is displayed when modifying SAMPLE RATE accurately represents the output; if a second unit of measurement is selected and SAMPLE RATE is modified, that second unit of measurement becomes the accurately displayed unit. For this reason it's recommended to choose the unit of measurement desired before setting the SAMPLE RATE value. 8) PULL UP/DOWN ­ The Pull Up/Down parameter is active only when SAMPLE RATE is set to INTernal or VIDEO. The frequency of the SAMPLE RATE may be modified by 4 defined percentages to accommodate specific situations encountered during video production and post. [. . . ] Worse, if a hand-cranked film camera were used to capture a performance, even the most stable projector couldn't remove the instability of the movement recorded on film. Likewise, jitter anomalies encoded during the analog-to-digital stage can never be removed further down the digital audio chain. The overall quality of a digital system is determined by the quality of the A-to-D and D-to-A converters; the most stable clock possible ensures the most consistent timing, and therefore the highest quality, for these stages. Master Clock and Device Synchronization A Master Clock also ensures the synchronization of all devices in a studio, allowing any possible digital connection to be made seamlessly without clicks, pops or digital hash. [. . . ]