Also, the propagationĭelays of digital line drivers and receivers are usually pretty constant, so it is easy to generate an accurate
Unmodulated code frames are also called DC Level Shift signals, or DCLS signals.ĭue to its nature as digital signals the DCLS time codes have well-defined slopes. Since the logic levels of the raw data stream are often represented by DC voltage levels, the The chapter Choosing A Code Format provides some guidelines which code formats should be used preferably, if possible. Some newer code formats also provide a 2 digit year number. Optional extensions include a Control Field (CF), and a Straight Binary Seconds (SBS) field. However, even though often used in device specifications, a name like IRIG-B alone doesn't tell whether the signal is modulated, or DCLS, and which pieces of time information are included.įor IRIG-B, the first 2 digits determine if a signal is modulated ( B12 x), or unmodulated ( B00 x), and the 3rd digit x determines which data is included.Īll IRIG time code formats include the time-of-day and day-of-year information anyway, which is often referred to as BCD or TOY. IRIG-A and IRIG-G use different frame rates. For example, all the popular IRIG-B codes are based on a 100 PPS frame rate, while e.g. Which particular time code should be used preferably for an application depends on the specific requirements of that application. The time codes defined by these standards are based on specific IRIG codes, but include some useful extensions. Range Commander Council's publications web page: īeside the original IRIG time codes there are additional standards like IEEE 1344 or IEEE C37.118, published by the Institute of Electrical and Electronics Engineers (IEEE), as well as AFNOR NF S87-500 published by the French standardization organization Associacion Française de Normalisation (AFNOR).
The current version of the document is IRIG Standard 200-04 which was published in 2004 and is available for download at the U.S. Over the years there have been a number of revisions and extensions to the original specification. The individual name determines the transmission speed and frame rate, whether the time code is modulated or unmodulated (DC level shift, DCLS), and the kind of information included in the transmitted data.īack in 1956 the TeleCommunication Working Group (TCWG) of the American Inter Range Instrumentation Group (IRIG) was mandated to standardize different time code formats, resulting in IRIG Document 104-60 which was published in 1960. Individual IRIG code formats are distinguished by names consisting of a letter followed by a 3-digit number.
Or even better: the 7Q knows and corrects the timecode all by itself based on thegiven cam and rec.The frequently used term IRIG signals refers to a whole group of serial time codes which use a continuous stream of binary data to transmit information on date and time.
I think it will be necessary to have the possibility in the 7Q to give an offset to a tc along with the recorded videosignal. With the upcoming fs5 and other similar cams used with the 7Q this will keep giving issues in the future. I suspect the combi 4k raw and processing in the 7Q gives an unwanted latency and this should be compensated.
On that camera the tc was fed through te tc in from the camera and the outboard 7Q+ got its tc embedded in the sdi signal from the output of the F3camera. Very unprofessional as there was a lot of effort put into the syncing on set! A F3 camera used on the same dualcam shots was deadsync. In post they are now struggling with audio to offset it manually. However the timecode was like 2 frames off (late). The timecode was fed into the LTC in from the 7Q+ (Due to the lack of tc in on the fs700). The recording was set to 4k to HD in prores 422. The cam was a fs700 with 4K raw out to the 7Q+. Last shoot I noticed a timecode difference between the denecke timecode slate and the recorded signal.