State of the art -radio

[Allison]

>
>Subject: Re: State of the art -radio
>   From: woodelf <bfranchuk at jetnet.ab.ca>
>   Date: Sat, 24 Sep 2005 00:25:05 -0600
>     To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Well add another Crystal -- Filter that is -- :)
>I agree that DSP is great for brick wall filters but you might want
>to check up on Crystal Sets on the internet because I read a
>few people saying that the design of the radios in the past
>are based on incorrect theory.

Still wouldn't help. there are limits, Good, Fast, Cheap, Pick any two.

>> Non-linearity it's bad design for some things but useful where 
>> efficientcy counts.  Look at Class E trannsmitters and switchmode 
>> power supplies for efficientcy.
>
>That is only because you need a sine wave out of the transmiter
>something that is easy to restore with a tuned circuit. You had better
>not look at what I consider a state of the art HI-Fi amp to be, the
>one I built from plans I found on the web. A whole 1.25? watts RMS
>per channel. I consider it state of the art because 1) It has a
>regulated power supply ( Zener diode - 800 volt 6.5 amp  FET pass
>tranistor ) 2) Single ended ultra-linear ( 50%) operation.
>A 6SL7 driver and 6V6GT for the power amp.

State of the art in 1969. Pushpull Triode connected 813s, negative 
feedback to cathode, Zener bias regulation, stiff 1200V ps.  Oh
flat from 15hz to 20khz -3db to 25khz at a mere 300w.  THD was 
down in the sub 0.05% range.  Only weighed in at 80 pounds.

In 1974 I worked on a 1KW solidstate that was 40 pounds and could 
easily beat the specs and overall sound of those 813s and stand 
shorts or overloads better!

>> What you should check out is Softrock, uses the soundard and CPU
>> to do the back end stuff and it's frontend is a 29$ kit.
>> 
>> www.amqrp.org/kits/softrock40/index.html  (it's sold out but the 
>> details are there).
>>
>
>But is it open source? I don't like CLOSED equipment or ideas.

Did you look, you would not have asked then.

>
>Some day I might want to break the glass and look inside.
>Still if you have the PC it a good use for it, since it
>too new to be a classic computer. :)

Maybe, today.   Then again I was working with 16bit DSP 
back in '81.


Allison