On Oct 7, 11:58*am, Bob wrote:
Hi,

A bit off topic, but I figure you folks are the true theorists out
there, and would probably know about this.

Am thinking about purchasing a shortwave defined radio receiver from
WinRadio (http://www.winradio.com/home/g33ddc.htm).

Here is copy from part of their spec sheet:

* * *"The receiver's robust front-end is equipped with an
ultra-high-linearity amplifier which results in exceptional
strong-signal performance. This already robust front-end is further
enhanced with a user-selectable preselector that can operate either in a
fully automatic or user-configurable mode. As many as 119 different
filter combinations can be constructed by the user (91 bandpass, 14
low-pass and 14 high-pass). The front-end employs 34 subminiature
electromechanical relays (rather than often used but distortion-prone
semiconductor switches) to ensure high dynamic range."

Was really surprised to see: The front-end employs 34 subminiature
electromechanical relays (rather than often used but distortion-prone
semiconductor switches) to ensure high dynamic range.

I am retired now, so haven't kept up withese things, or the state of the
art nowadays, but are they still using electromechanical relays for
front ends feeding a 16 bit A to D ?

Haven't semiconductor switches, caught up with reed relays for this
application by now, or do they "still" provide a lower "on" resistance,
etc. ?

Any thoughts would be most appreciated.

Thanks,
Bob
Excuse me, Bob, but no where in the description do they mention reed
relays. I really doubt they are using reed relays because of the open
capacitance of the contacts, plus, reed relays often stick shut
because of fatigue, static electricity, and if left closed for a long
time, metal migration will stick them closed.

Bet they are using regular relays, but in miniature form.

Paul