Beyonwiz Australia

My dual tuner has arrived form my V2. I have connected it, but I don't think it has been recognised - what do I need to do?
It tells me I only have tuners A & B, and I presume they're the built-in tuners. I'm sure I've seen somewhere the extra step needed to get the V2 to recogise the USB tuner/s, but can't seem to find it now.

You need to this the V2. Your cannot plug in or unplug the tuners while the V2 is running or else they will not work properly, or the V2 may crash.

I found the re-boot option, and tuners C & D have been found.

After setting-up recordings from 4 networks simultaneously, I have now found you don't need to worry about the 0% signal strength for the USB tuners because the signal strength measurement obviously doesn't work for USB tuners. It's all working just nicely.

The lower bar isn't a signal strength reading for the USB tuners. It's actually a signal quality meter for whatever channel you are currently watching. The upper bar use the signal strength for the current channel.

Unfortunately there is a bug with the signal quality bar in that it always reads zero when the internal tuner a or b is active.

What's the difference between signal strength & signal quality ?

steerage250 wrote: ↑

Fri May 29, 2020 21:38

What's the difference between signal strength & signal quality ?

Strength is how "loud" the signal is (so to speak...I don't meant the audio volume), while quality is how "clean" the signal is.

If a signal is weak then it is naturally harder for the tuner to "hear" it this leading to bad reception.

A strong signal can still be full of lots of noise and the tv tuner will have trouble decoding it because the quality of the signal is low.

The quality of the signal is essentially a ratio of the signal strength to the strength of the noise (signal to noise ratio plus dinner maths magic).

steerage250 wrote: ↑

Fri May 29, 2020 21:38

What's the difference between signal strength & signal quality ?

A receiver needs a certain minimum amplitude signal or it can't decode the embedded data. Equally though, if the amplitude is excessive it can overload the detection circuitry. In practice, sometimes the measure being presented is actually the automatic gain control signal used as a proxy for strength. Digital receivers tend to be "all or nothing" devices whereas for analogue devices quality is closely linked to signal strength.

The next step is that the digital circuitry decodes the audio and video from the carrier signal. Being encoded digitally, the signals are quantized in bits. The signals contain checksums that tell the decoder whether the received signal exactly matches the transmitted signal. The decoder typically can correct a modest amount of errors. This is used as a measure of quality whereby more errors corresponds to lower quality.

Therefore, digital has a greater need to measure quality and quantity separately.

thanks for both of your replies

Paul_oz53 wrote: ↑

Fri May 29, 2020 22:46

The next step is that the digital circuitry decodes the audio and video from the carrier signal. Being encoded digitally, the signals are quantized in bits. The signals contain checksums that tell the decoder whether the received signal exactly matches the transmitted signal. The decoder typically can correct a modest amount of errors. This is used as a measure of quality whereby more errors corresponds to lower quality.

That's certainly a good indicator of signal quality, but it's not what's displayed in the signal quality indicator. The signal quality displayed is the signal-to-noise ratio. I'm not sure how or where it's measured.

The signal quality derived from the checksums (actually from the forward error correction) is not displayed in the pre-loadad skins. That value is an approximation of the Bit Error Rate (BER). There are two variants that can be measured at the receiver end: the total number of detected errors and the number of error bits that could not be corrected.

As an aside: the receiver alone cannot detect all errors: some can pass through the error correction undetected.

The firmware can report the BER, and I think that it's the first sort (all errors, whether corrected or not), but I'm not sure about that or what the units or sampling period are for what's reported.

BER warnings are displayed in the infobar, channel selection screen and single-channel infobar EPG in IanSav's OverlayHD skin. The text "BIT ERRORS DETECTED!" flashes black on a red background when the BER reported by the tuner driver is above 375. I think that Ian set that value by trial-and-error.

I was speaking generally and trying to "keep it simple" but yes, signal to noise ratio is another measure of quality.

I didn't realise the Wiz actually uses SNR. At first glance, not necessarily a particularly good measure as it can show high while bit errors are rampant. Happy to be corrected.

In practice, picture breakup is my real measure of quality as it is the user experience that matters above any arbitrary measure. Of course, if a previously good reading were to drop substantially, that suggests a technical problem has arisen.