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Re: [TenTec] AM Receiver distortion in Orion II

To: tentec@contesting.com
Subject: Re: [TenTec] AM Receiver distortion in Orion II
From: "Rob Atkinson, K5UJ" <k5uj@hotmail.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Wed, 24 Jan 2007 19:33:34 +0000
List-post: <mailto:tentec@contesting.com>
Hi,

I'll try to explain this. think of a dsb circuit as a data processing circuit.

If you have two circuits, one using 16 bit processing and the other 24 bit, but they both have the same clock speed, then the 24 bit circuit processes more data for a given amount of time. That means the digital simulation of an analog waveform for a fixed time period has greater precision beause it is sampling at the same rate, but processing it more rapidly, 1/3 more for each clock tick. Processing bigger chunks of data at a time means you can do things like employ more complex processing algorithms that can result in a more faithful analog result.

Assuming a CD player is a 16 bit system, it could be extremely high fidelity, if it's clock speed is extremely high because then, it would be sampling and processing more data than a 24 bit circuit on a much slower speed for a given amount of time.

So besides the word length, we also need to know the clock speed for the dsp circuits, which I for one, do not know off hand (I think the 870 dsp runs at 10 MHz but don't hold me to that).

a few folks have mentioned that the Orion is (depending on who you talk to) a 24 or 32 bit dsp processor. That's great and I humbly apologize for implying anything else, but its clock speed is also important and in any event, there seem to be other components that limit its flat frequency response.

73,

rob / k5uj


On 1/24/07, Rob Atkinson, K5UJ <k5uj@hotmail.com> wrote:
It's not too surprising that there's a difference between the Orion's AM
audio and the TS870.
There are probably at least two reasons for this. The 870's dsp is a 24 bit
system; Ten Tec went with 16 bit dsp, which produces a slightly "grungy"
sound at times.

Sorry, but it makes no sense to me to attribute these audio qualities
to the DSP word length.

CD's use 16-bit sampling and don't sound "grungy".

73,
Barry N1EU

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