Remembering NICAM: Deep-Dive Into A Broadcasting Legacy

A VCR with NICAM support.

Although for many the introduction of color television would have seemed to be the pinnacle of analog broadcast television, the 1970s saw the development of stereo audio systems to go with TV broadcasts, including the all-digital NICAM. With NICAM broadcasts having ceased for about a decade now, the studio equipment for encoding and modulating NICAM can now be picked up for cheap. This led [Matthew Millman] to not only buy a stack of Philips NICAM studio gear, but also tear them down and set up a fully working NICAM encoding/decoding system with an Arcam Delta 150 as receiver and Philips PM5687 encoder.

Philips PM5687 with lid off.
Philips PM5687 with lid off.

Finally, the Philips PM5688 test receiver is analyzed. This is the component that studios would have used to ensure that the NICAM encoding and modulating systems were working properly. Although public NICAM broadcasts started in the late 1980s, the system was originally developed to enable point to point transfers of audio data within a transmission system. This was made very easy due to the digital nature of the system, and made enabling it for public broadcasts relatively straightforward once receivers became affordable enough.

Of note is that NICAM was only ever used in Europe and some Asian-Pacific countries, with others using the German Zweikanalton. This was a purely analog (two FM channels) system, and the US opted to use its MTS system, that was quite similar to the German system in terms of transmitting multiple FM channels alongside the TV signal. With digital TV gradually overtaking analog TV transmissions, the future of NICAM, MTS and others was sealed, leaving us with just these time capsules we can build up using old studio equipment.

17 thoughts on “Remembering NICAM: Deep-Dive Into A Broadcasting Legacy

  1. Looking back I’m amazed NICAM 728 was ever a thing when simpler/cheaper analogue stereo systems already existed. I’m glad it did though, it really does sound amazing. Also fully documented so anyone could implement it – as all public broadcast standards should be.

  2. Backwards compatibility was always the stumbling block on US television technology. Why they never went with PAL and stuck with NTSC during the color adoption era was because they didn’t want the existing TV sets to go dark once Color was introduced.

    1. It was more likely due to protectionism and political reasons. When PAL was ready not that many NTSC sets were already deployed. Having to pay license fees to a German company was probably out of the question. As always, history repeats itself and now North America has ATSC.
      btw, the French weren’t any better. Positive video modulation, AM sound and SECAM. Using a German or US patent was impossible, mon dieu!

      1. Ironically, though, the East Germans had SECAM TVs. Or, more accurately said, most mortals over there merely had B/W TVs for a long time. Either because they used to continue old equipment, or because they got some from UdSSR. Like those unreliable Junost TVs. ;) Anyway, the official colour standard was SECAM. To watch PAL transmission from West Germany required a converter device. Some companies even sold SECAM TVs with PAL compatibility. For receiving ARD, ZDF et cetera. Without a converter, reception was possible, but in monochrome only.

        Interestingly, the DDR (GDR) was the last nation to keep pure B/W transmitters. If a film was in native monochrome format, these were used. Which seems very odd from a practical point of view. But technically, it made sense. Pure monochrome was of much higher quality than PAL/NTSC or SECAM. They all lost resolution in comparison to the old standard.

        Personally, I wished that NTSC and PAL had died much earlier than they did. In comparison to a grayscale picture on a monochrome video monitor, they’re disgusting. At least at the given bandwidth. Looking backwards, PAL ashames me, as a German. Japan had been much wiser in that respect. Kudos to them.

      2. The longer tv existed, the bigger the user base. To switch meant all those people had to switch too.

        TV existed in the US before WWII, then the allocation changed. The FM band was liwer, moved to 88-108MHz after WWII, so the old receivers were scrap.

        The US learned, so any changes to TV had to ride on the existing system. Color, stereo, closed captions.

        DTV was a break from 70 year old technology.And the only way it happened was “free DTV converters for everyone”

  3. This article has gone a bit wayward with the facts- NICAM was a UK invention, developed mainly by the BBC for broadcasting digital audio within it’s UHF 625 line network known as PAL I. It was conceived in the late ’80’s and the rollout was started around 1990. The initials NICAM stands for something like Near Instantaneous Companded Audio Multiplex or similar. Decoders were installed in top end CRT TV sets but mainly in HiFi audio VHS recorders. By the end of the decade DVB on satellite & the UHF terrestrial network meant it’s days were numbered along with Teletext/Fast-text and PAL Plus. The sound quality was very good.

  4. In case anyone is curious (I was so I googled it up) there is NO audio compression taking place other than compaunding 14bit raw audio down to 10 bits +1 bit parity and shitting resulting 728Kbits/sec raw data stream using DQPSK modulation. Its in the name “Near Instantaneous Companded Audio Multiplex”. 1ms delay (buffer size) 14 (10 real) bits 32KHz. Very uninspiring, but extremely simple to implement in late eighties on the cheap.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.