Home Products Services Support Info
Rostec Engineering   Administration: Christianehøj 43, 2860 Søborg, Denmark   -   Email rostec@rostec.dk   -   Phone +45 3967 6438
  ROSTEC ASD24 Reference Generator                       High Precision Video/Clock/AES sync generator
Rostec ASD24 is a high performance and high precision Digital Reference Generator intended for use as a master reference in Broadcast, Film, Video/Audio editing and multi media recording studios. The unit is based on an accurate Grade 1 oven crystal oscillator, and it features a comprehensible range of SD/HD video sync output formats and Clock/AES/SPDIF output frequencies. It is able to synchronize to all the normally audio word clocks, including the 10 MHz from GPS disciplined precision sources like Rubidium or Cesium oscillators (so called atomic clocks) and the standard reference clocks from E1 and T1 Telecom systems. The user interface is straight forward and intuitive with at clear “What You See Is What You Get” readout on a bright OLED display. None of that confusing +/- 1% or 10%.   You just select the format you want. That’s it. The display shows an unmistakable and real-time status of the chosen parameters, like video format, video frame rate, clock/AES/SPDIF output and clock sync input. The lock/error status of the chosen sync source, i.e. internal or external reference, is also shown in real time
Click for larger pictures
Multiple units from the half-size box series fit nicely in 19” rack systems
Features * Easy and intuitive user interface * Clear real time read-out of status on a bright OLED display * 1 Sync input, BNC connector, 1.5 kohm, unterminated • 2 Video outputs. BNC connectors, 75 ohm • 6 clock outputs, BNC connectors, 75 ohm • 1 AES 11 output. XLR male connector, transformer balanced 110 ohm • 1 S/PDIF output. RCA connector, 75 ohm • 24 Video sync output formats • 16 clock output frequencies * 6 AES/SPDIF output frequencies * HD video tri-level sync * SD video standard negative going sync • Video test pattern, color bar for SD formats, hatch pattern (grid) for HD formats. • Grade 1 internal oven reference crystal oscillator. • Able to synchronize to standard word clocks, 10 MHz GPS (atomic clocks) and 2.048 MHz E1/1.544 MHz T1 Telecom clocks • Sync input accept from 0.2 Volts to 10 Volts. • Sync Input has a "sweet spot" detector, providing auto-slicing and signal clean-up for safe and jitter-free synchronization. • Fly wheeling and soft glide when switching between external and internal sync reference. Always continuous output! No drop-outs • Extremely low output jitter and wander, typically less than 80 psec RMS • Exceptional high immunity against jitter and digital noise from computer work stations. • Linear low noise analog power supply. • Internal magnetic and electrical screening. • Inputs and outputs are ESD protected to 23 kV IEC 61000-4-2 and 15 A surge IEC 61000-4-5. • Sturdy steel metal casing, electrically and magnetically screened. • Stand-alone desktop, half size 19” standard. • Small footprint. Dimensions: 210mm x 210mm x 42mm
General description The heart of the ASD24 is a high grade crystal oscillator built into a temperature controlled oven together with all the necessary voltage references and regulators for its operation. This scheme results in excellent frequency stability over the specified temperature range, far superior to a standard temperature compensated crystal oscillator. The frequency accuracy is better than 0.1 ppm from 0 to +50 C. The factory adjustment is typically 0.05 ppm at 25 C. The ASD24 always uses this oscillator as the central source for all Video, Word and AES/SPDIF outputs, no matter whether the generator runs on its own or if it is locked to an external sync source. The sync input is meant to be used with an ultra high accuracy house clock, if such is available. When the generator locks to the external sync, it simply tunes the internal crystal oscillator to the exact frequency of the incoming reference. The incoming sync accuracy is then directly transferred to all outputs, independent of which format is chosen. For example, if you sync the generator to an external  GPS disciplined Atomic Clock with an accuracy of 10E-12 (1/1.000.000 ppm), ALL OUTPUTS wil have an accuracy of 1/1.000.000 ppm. Further, the generator does not jump into lock, but glides softly until a perfect lock is achieved. If the external sync signal is lost or discontinued, the generator softly glides back to the internal reference, and while it is gliding back and fort between sync sources , it continues to supply uninterrupted outputs. No interruptions, no disturbances. Word clock, AES and SPDIF signals are generated by a separate crystal oscillator block, which is permanently locked to the video encoder by means of a high precision low jitter phase locked loop. When the video format is changed, the Clock/AES/SPDIF outputs always follow with the correct mathematically relationship between video frame rate and clock frequency. Video, Clock, AES and SPDIF are bound together like cogs in a gearbox, always correct. never wanders off. When an integer relationship exists between video frame rate and AES block frequency, the AES block start (Z-preamble) is positioned at the video frame start. When an integer relationship exists between video frame rate and word clock, the leading edge if the clock (and the X-preamble of AES) is positioned at the video frame start. This is all in full accordance with the AES recommendations. Note that the ASD24 does NOT use the problematic and inaccurate approximation techniques found in DDS (direct digital synthesis) or fractional frequency dividers. Using this technique invariable results in an unacceptable level of jitter. Instead, the architecture of the ASD24 is based on SAW oscillators (surface acoustic wave), hardware synchronous counters and phase-lock loops in order to maintain the correct mathematical relationship between Video, Clock/AES/SPDIF outputs and sync input clocks. This topology maintains total and accurate control of the relationship between all signals, so no drift between video and audio is possible!  ALL combinations between Input Sync, Video Format, Clock and AES/SPDIF outputs are allowed and valid. The internal locking mechanism keeps all signals in an iron grip, with a mathematical relationship that cannot be broken apart. ASD24 always maintains the correct relationships between all signals, like cogs in a gearbox!
Electrical and mechanical specifications Sync Reference input * Clock input, 1.5 kohm unbalanced, unterminated, 1 x BNC connector * Input level 0.5 V - 10 V PP, square or sine * Input reference: INTERNAL and 13 external clock frequencies, listed below* * Clock input capture range: +/- 80 ppm. * Lock time approx:  0.4 - 0.6 sec. Video Sync Output: * Video Sync Output, 75 ohm, SMPTE/EBU level, 2 x BNC connectors, individually buffered * SD bi-level, negative going sync. * SD, Colorbar test pattern (selectable) * HD tri-level sync * HD, HATCH test pattern (selectable) * 24 Video Sync output formats and frame rates, listed below* Word Clock Output: * Word clock output, 75 ohm, 6 x BNC connectors, individually buffered * Output level 5 Volt PP no load, (TTL level). 2.5 Volt PP into 75 ohm * 16 word clock output frequencies, listed below* AES output: * AES3 format, transformer balanced, 110 ohm, 1 x XLR Male connector * Output level 10 Volt PP no load, 5 Volt PP into 110 ohm (full swing buffer) * 6 AES3 output frequencies, following the word clock frequencies as listed below* SPDIF output: * SPDIF output format, 75 ohm, 1 x RCA female plug * Output level 1 Volt PP no load, 0.5 Volt PP into 75 ohm * 6 SPDIF output frequencies, following the word clock frequencies as listed below* Clock system: * Internal GRADE 1, oven crystal oscillator. * Accuracy: Factory calibrated to 0.05 ppm @ 25 deg C * Temperature stability: +/- 0.1 ppm from 0 degC to +50 deg C. * Ageing: 1 ppm per year. * Internal crystal oscillator jitter: 2.4 ps rms. * Video sync output jitter and wander: 80 ps RMS * Word clock output jitter and wander: 80 ps RMS * AES/SPDIF output data jitter and wander: 80 ps RMS. Power supply: * Linear analog, passively cooled, high power, very low noise. * Thermally and overload protected. * Mains voltage: Nominal 230 VAC, range 180 - 264 VAC 50-60 Hz (115 VAC version available by request). * Power consumption: 10 Watts. General: * Sturdy steel casing, magnetically and electrically screened. Size 210 mm x 210 mm x 42 mm. * Analog (PLL circuits) and digital circuits are magnetically and electrically isolated by internal metal screening and separate ground systems. * All signal inputs and outputs are ESD protected to 23 kV 15 A surge (IEC61000-4-2 and IEC61000-4-5).
The user interface is simple. informative and easy-going. For example, when you select a video sync format with the arrow buttons, the video standard is shown in the display together with the selected video format and frame rate.  When you are satisfied with your choice, just press the RTN button, and the unit will return you to the main menu, showing an overview of all the parameters you have chosen. More info can be found in the quick guides and in the manual.
Sync references (SOURCE on the front display) 1.   INTERNAL      internal oven crystal oscillator 2.   44.1 kHz         standard audio sampling frequency 3.   48 kHz            standard audio sampling frequency 4.   88.2 kHz         standard audio sampling frequency 5.   96 kHz            standard audio sampling frequency 6.   176.4 kHz       standard audio sampling frequency 7.   192 kHz          standard audio sampling frequency 8.   352.8 kHz       audio sampling frequency from future audio equipment 9.   384 kHz          audio sampling frequency from future audio equipment 10. 705.6 kHz       audio sampling frequency from future audio equipment 11. 768 kHz          audio sampling frequency from future audio equipment 12. 1.544 MHz      clock from T1 Telecom systems 13. 2.048 MHz      clock from E1 Telecom systems 14. 10 MHz           clock from GPS receivers, rubidium oscillators, cesium oscillators (aka atomic clocks)
Video Sync Outputs (VIDEO OUT on the front display) 1.   PAL B PAL B 25i interlaced 2.   NTSC NTSC 29.97i interlaced 3.   525p 59.94 ITU-BT 1362 progressive 4.   625p 50 ITU-BT 1362 progressive 5.   720p 23.98 SMPTE 296M-8 progressive 6.   720p 24 SMPTE 296M-7 progressive 7.   720p 25 SMPTE 296M-6 progressive 8.   720p 29.97 SMPTE 296M-5 progressive 9.   720p 30 SMPTE 296M-4 progressive 10. 720p 50 SMPTE 296M-3 progressive 11. 720p 59.94 SMPTE 296M-2 progressive 12. 720p 60 SMPTE 296M-1 progressive 13. 1035i 29.97 SMPTE 240M interlaced 14. 1035i 30 SMPTE 240M interlaced 15. 1080i 25 SMPTE 274M-6 interlaced 16. 1080i 29.97 SMPTE 274M-5 interlaced 17. 1080i 30 SMPTE 274M-4 interlaced 18. 1080p 23.98 SMPTE 274M-11 progressive 19. 1080p 24 SMPTE 274M-10 progressive 20. 1080p 25 SMPTE 274M-9 progressive 21. 1080p 29.97 SMPTE 274M-8 progressive 22. 1080p 30 SMPTE 274M-7 progressive 23. 1080psf 24 ITU-R BT.709-5 interlaced 24. 1080psf 23.98 Non Standard interlaced
Word Clock Outputs (CLOCK OUT on the front display) 1.   44.1 kHz       standard audio sampling frequency 2.   48 kHz          standard audio sampling frequency 3.   88.2 kHz       standard audio sampling frequency 4.   96 kHz          standard audio sampling frequency 5.   176.4 kHz     standard audio sampling frequency 6.   192 kHz        standard audio sampling frequency 7.   352.4 kHz     audio sampling frequency for future audio equipment 8.   384 kHz        audio sampling frequency for future audio equipment 9.   705.6 kHz     audio sampling frequency for future audio equipment 10. 768 kHz        audio sampling frequency for future audio equipment 11. 1.4112 MHz  audio sampling frequency for 1-bit converters 12. 1.536 MHz    audio sampling frequency for 1-bit converters 13. 2.8224 MHz  mostly for test bench/lab work 14. 3.072 MHz    mostly for test bench/lab work 15. 5.6448 MHz    mostly for test bench/lab work 16. 6.144 MHz    mostly for test bench/lab work
 AES/SPDIF Outputs (follows CLOCK OUT on the front display) 1.   44.1 kHz       standard audio sampling frequency 2.   48 kHz          standard audio sampling frequency 3.   88.2 kHz       standard audio sampling frequency 4.   96 kHz          standard audio sampling frequency 5.   176.4 kHz     standard audio sampling frequency 6.   192 kHz        standard audio sampling frequency At word clock output frequencies above 192 kHz, the AES/SPDIF outputs stay at 176.4 kHz for 44.1 kHz base frequencies and stay at 192 kHz for 48 kHz base frequencies.