PRODUCT
DESCRIPTION
The IRIG B Timecode Processor is a
factory-fitted option for the AE21240 Controller assembly now
fitted to all AE3000FL Series Recorders. When this option is fitted, the recorder control programme
detects its presence at power-up and the appropriate additional
functions become available through the MENU structure. All parameters
are set from the front panel buttons. Timecode and Audio channels are carried on a pair of linear edge
tracks. The following modes of operation are available:
Avalon
Timecode
By default, the Timecode channel is used to
generate, record and display Avalon's proprietary timecode data
(compatible with previous Avalon recorders). When the recorder is
stopped or recording, the display shows Time and Date information
derived from the recorder’s internal real-time clock (RTC). In other modes (Play, Cue / Review, Fast Forward or Rewind)
recorded values are displayed. If no timecode is recorded, or the
wrong selection is active, then the display will be all zeros.
IRIG
B Generator
The Timecode channel can also be used for
recording and displaying Time and Date information in Avalon's 'Enhanced
IRIG-B' format. The time from the recorder’s RTC is used to
generate the IRIG-B signal (1 kHz amplitude modulated). The IRIG
Day number is computed from the RTC Day and Month values ( Day 1 being
Jan 1st). Although the standard IRIG-B format does not
support 'Year' or 'Event' information, Avalon places this data into
normally unused slots in the IRIG signal. The display shows the
information being recorded, the Date section being modified to show
YY:DDD where YY is the RTC year and DDD is the 'day of the year'
value, as follows:
Avalon Standard Display Format:
10:58:23
980403 3701
Avalon 'Enhanced IRIG' Display Format:
10:58:23
98:093 3701
(note that the MMDD date '0403' in the Avalon
standard format becomes the familiar IRIG-B Day format '093' in
Avalon's 'Enhanced IRIG' mode, along with the additional (non-IRIG)
Year and Event information.
In play modes, the display shows the recorded
values, at a display update rate of approximately 1 Hz. The play
signal is available at the Timecode OUT connector (pin A4 on the
rear-panel mounted D-series connector SK2) for use by an external IRIG-B
Reader.
IRIG
B Reader
The Timecode channel can also be used for
handling the user’s own IRIG-B timecode signals, connected to the
Timecode IN connector (SK2, pin A2). The incoming signal is recorded
directly to tape, and is also decoded to drive the display Time and
Day. The Year and Event values will be zero unless the user’s source
has information in the relevant data slots. In play modes, the display
shows the recorded values as already described.
IRIG-B Format (Augmented)
Not to be confused with Avalon's 'Enhanced IRIG'
mode, here the Timecode channel accepts the user’s IRIG-B timecode
and splices in the recorder’s Year and Event data in order to
generate a composite signal similar to the Generator output in the
'Enhanced IRIG' case. The essential difference however is that the
user’s own timing reference is maintained to within a few
milliseconds of processing delay. The display shows a combination of
the user's Time and Day values together with the recorder's Year and
Event data. In play modes, the display shows the recorded values.
Time
setting
It is also possible to set the Recorder’s
internal clock time to that of an external IRIG-B source. This is
achieved by selecting EXT IRIG from the appropriate menu page. The
IRIG Processor switches to Reader mode and waits for a valid time with
a seconds value of 5. When this is detected, the internal clock time
is set to the reader time with a seconds value of 6 as the time value
is transferred on the frame mark following the read value. By setting
several recorders from the same source, the internal clocks can be
aligned to within a fraction of a second. Only the time (hours, minutes and seconds) changes, since the
IRIG Day number may not be the actual day-of-the-year.
Time
Code Off
For applications where there is no requirement
to record and display time and date, the Timecode channel can be set
up to record and reproduce an audio frequency signal via the Timecode
IN and Timecode OUT connections (SK 2, pins A2 and A4). In this mode,
the Time, Date and Event line on the display is blank.
ADDITIONAL INFORMATION
Auxiliary
Channel B (AUX IN, AUX OUT)
In addition to the Timecode channel described in
this datasheet, Avalon AE3000FL Series Recorders also have a second
'housekeeping' channels designated the Auxiliary (or Voice) Channel B.
The button sequence CONF/more/AUX toggles the AUX channel between the
normal audio operation and RS232 logging.
Audio
logging
The AUX IN signal is routed to the recorder’s
auxiliary audio channel (SK2, pin A1) and returned to AUX OUT (SK2,
pin 3). The specification is unaltered from that of the standard
recorder.
RS232
logging
On AE3000FL Series fitted with the optional IRIG-B
Generator/Reader facility, it is also possible to recorder and play an
RS232 level signal. This input is connected via SK2, pin 7 (0v pin 9)
and is recorded as an FSK carrier on the Auxiliary B channel. The
serial data may be at any rate up to 1200 baud and in any data format.
In Play, the FSK signal is demodulated and returned to SK2,
pin 8. As the signal is recorded on the outermost longitudinal track,
the recovered data may have occasional error bursts (characters missed
or scrambled) which the user’s software should be able to allow for.
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