PAL Tuner

From NZTivo

Is it possible to get stereo reception (via a PAL Tuner) in New Zealand?

Answer: With UK Units - Yes

The UK (Thomson) TiVo units work well with the digital PAL B/G NICAM signal broadcast by all New Zealand Free-To-Air stations. I get perfect surround sound from all of the stations that I receive. To correctly tune to New Zealand stations with NICAM support you will need to load the ukchan-2.5.5_nz-nicam module (this can be done by adding "insmod ukchan-2.5.5_nz-nicam.o" in your startup scripts).

The ukchan-2.5.5_nz module must be compiled with NICAMSTEREOMODE defined. Without NICAMSTEREOMODE it uses 0x00200003 which selects Zweiton analogue stereo - which results in mono in New Zealand. If you want it set to automatically detect then you need to use 0x00200001. This will recognise the format and switch to it within 0.5 seconds.

I prefer to force it to Nicam using 0x00200008, as all of our broadcasts are using this. If you wish to test this for yourself then you can use the iicset4 utility (the last two should sound the same, but the first will switch to mono):

1. iicset4 0x88 0x10 0x00200003
2. iicset4 0x88 0x10 0x00200001
3. iicset4 0x88 0x10 0x00200008

FYI : With a NICAM signal the sound is digitised to a 14 bit accuracy

and sampled at 32KHz. The upper frequency limit of each channel is 15KHz due to anti-aliasing filters on the encoder. The original 14 bit samples are companded digitally to 10 bits for transmisson - this ensures that the encoding and decoding algorithms can track perfectly.

Answer: With US Units - No

Note: The Australia stereo modifications made to US units will not work in New Zealand, as Australia use Zweiton Stereo (5.742MHz offset) whereas New Zealand use NICAM (with a 5.85MHz offset). The Australian (analogue) stereo modification will not work with the New Zealand digital NICAM system. 

So while the PAL tuner conversion does allow New Zealand users to tune to the FTA stations, the audio output will need to be wired for mono.

The reason is that in Australia the base carrier (5.5MHz) carries a mono signal (Left+Right)/2 and the second carrier (5.742MHz) carries the Right hand channel. In New Zealand we have digital stereo encoded with Nicam, meaning that the base carrier (5.5MHz) carries a mono signal, but the second carrier (5.85MHz) carries a digitally modulated Left and Right channel - which is how we get a digital stereo signal.

Currently it looks like the MSP3430G chip will need to be replaced with a MSP3450G chip (or possibly a MSP3410D as found in the UK systems) in order to decode PAL-B/G NICAM. This is an 80pin surface mounted chip - so not a job for the casual hacker. These chips are very hard to get in small quantities.