NICAM sound

[Darren King]

That's a nice bit of hardware. Great job!

I'll link this thread from my website as the source of information for the PAL tuner with NICAM decoding solution discussion area.

I am assuming that the hook up will be very similar to the old "Mark 1" Australian stereo decoder and if some pictures and info can be sent to me I'll happily update the how-to to incorporate the changes, or I'm happy for someone to use the current how-to and re-write it.

As for myself I unfortunately can't be in a position of active participation due to Australia not using NICAM so someone in NZ will have to take on the role of answering technical questions.

While I realise this decoder and a different PIC chip can program it for use in Australia I have enough stock of 3410D Micronas chips to last out the remainder of any future conversions that come my way. Although if Catdog wants to develop an Australian version (or a universal version that can do many standards) then go for your life mate

Once again, great work. Well done

[catdog]

I am assuming that the hook up will be very similar to the old "Mark 1" Australian stereo decoder and if some pictures and info can be sent to me I'll happily update the how-to to incorporate the changes, or I'm happy for someone to use the current how-to and re-write it.

Yes, exactly the same although it requires both 12V and 5V.

Although if Catdog wants to develop an Australian version (or a universal version that can do many standards) then go for your life mate

One step ahead of you - it autodetects the sound standard so should work in Australia as is!

[DOlsen]

I have installed one of these decoders in my Tivo, and can say it works really well. After putting in the pal turner and using the demodulated (mono) sound from the tuner, I thought that the sound was pretty good. Putting in the NICAM decoder and listing to it, the sound is so much better…

The decoder performs flawlessly. Locking onto the NICAM signal occurs virtually instantly. There is no noise output while changing channels, and the decoder falls back automatically to mono if the station does not broadcast in NICAM.

Very happy with the decoder.

[dozley]

Hi. I live in Wellington, and have previously had a PAL tuner installed in my Tivo.
I'm quite keen on getting Nicam stereo working. What's the easiest way, and what would the costs be?
Ta.

[Skolink]

If Catdog doesn't have any prototype boards left, you may want to wait until I build some 'pretty' NICAM decoder boards.
It will likely take a couple of months by the time I lay out the PCB, and then slip some PCBs in with a work job for fabrication, then assemble the boards.
Not sure of costs, have yet to look into component sourcing - NZ$ is high vs US$ which should help.

[Skolink]

I have installed one of Catdog's prototype NICAM decoders, but I now have no audio from the tuner. Could this be because this TiVo has a 'MKII stereo' mod where the MSP3430G is replaced by a MSP3430D? I assume that the MSP3430D is trying to decode the tuner SIF rather than using the audio coming in on pins 56 and 57. Is there some way to override this automatic setting?
I have removed Q14 and L28 (the opposite of upgrading a MKI stereo mod to a MKII).

[catdog]

I have installed one of Catdog's prototype NICAM decoders, but I now have no audio from the tuner. Could this be because this TiVo has a 'MKII stereo' mod where the MSP3430G is replaced by a MSP3430D? I assume that the MSP3430D is trying to decode the tuner SIF rather than using the audio coming in on pins 56 and 57. Is there some way to override this automatic setting?
I have removed Q14 and L28 (the opposite of upgrading a MKI stereo mod to a MKII).

Briefly looking at the Palmod source code:

	// Setup for tuner input
	if (mspType == MSP3410D) {
		iicw4(MSP_CHIP, WRITE_DEMOD, MODE | 0x8018);					// set device to slave mode
		iicw4(MSP_CHIP, WRITE_DEMOD, STANDARD_SELECT | AUTO_DETECT);	// autodetect sound standard
		//iicw4(MSP_CHIP, WRITE_DEMOD, AUTO_FM | 0x0001); 				// use error rate to determine sound
		iicw4(MSP_CHIP, WRITE_DEMOD, AUTO_FM | 0x0800); 				// select AM/FM sound
		iicw4(MSP_CHIP, WRITE_DEMOD, AD_CV | 0x00d0);					// set automatic gain control
		iicw4(MSP_CHIP, WRITE_DSP, I2S_SOURCE_MODE | 0x0020);			// select I2S source & AM/FM stereo
		iicw4(MSP_CHIP, WRITE_DSP, AM_FM_PRESCALE | (t_presc << 8));	// FM/AM Prescale
    }
    else {
		iicw4(MSP_CHIP, WRITE_DEMOD, MODUS | 0x0060);
		iicw4(MSP_CHIP, WRITE_DSP, I2S_SOURCE_MODE | 0x0220);			// select SCART source & AM/FM stereo
		iicw4(MSP_CHIP, WRITE_DSP, ACB | SCART_1);						// select SCART1 for the audio input
		iicw4(MSP_CHIP, WRITE_DSP, SCART_PRESCALE | (t_presc << 8));	// prescale SCART1
	}

Yes, it configures the tuner input source differently when it detects your MSP3410D, so will still be expecting a SIF input, hence no sound at the outputs. You will need to modify and recompile Palmod to force it to use the Scart input instead.

[thomson]

You will need to modify and recompile Palmod to force it to use the Scart input instead.

The attached palmod and palmod config can be used to configure this. A new option (s_audio) has been added. If this is set to 1 then SCART1 audio input is forced even if running with a MSP3410D.

It should be noted that this is not the official palmod and is a little different to that which is distributed with the OzTivo image. It should however be pretty compatible with all previous config files.

Updating palmod can stick your machine into a reboot loop if something goes wrong, so I would suggest you do something like that which is outlined here.

The "bin" file just contains the binaries (palmod and palmod_config) whereas the "src" file contains both the binaries and the source code. After making the setting by either using the Audio options menu under palmod_config, or by adding a s_audio=1 to your /etc/palmod.conf file you will need to reload palmod (or reboot).

[Skolink]

Thanks Thomson, the new menu is great! I wasn't looking forward to spending ages figuring out how to compile code for the TiVo (and guessing how to best change the code). I was getting twice-daily requests from my wife to get the TiVo going again.

Update: Upon testing the TiVo I found that the only sound I got from live TV was a stuttering sort of noise. Catdog made some further changes to Palmod which gave me silence instead. Upon further investigation I realised that I shouldn't have removed L28 when going from 'MKII stereo mod' to 'MKI stereo mod'. duh.

All working well now!

[KEG]

Hi all,
I would like to get my hands on one of these. How do I go about that. My Tivo already has the Pal tuner mod.

Cheers