The objective of this project
is to provide a pair of multiple-input audio
channels for my various receivers and transceivers: one HF
channel, and one VHF channel. These channels will have:
simultaneous, multi-receiver (source) capability
output amplification-per channel
volume controls per channel
simultaneous-filter selection options, including an NIR-12 dual-DSP
processor per channel (e.g. one HF & one VHF)
speaker (destination) selection
muting-on-transmit of both, either, or neither output channel
(600 ohm) output for multiple TUs with TU selection
switch-relay/connector capability via WW board
via 2 Philips DCC decks w/remoting of operational functions
The physical design will use a
19 inch rack cabinet, and will incorporate relay switching for virtually all
input and output lines. The unused inputs will be switched to ground through
20 ohm 2W resistors as loads. All audio I/O lines will use gold-plated
RCA-type jacks, and most other lines will use gold-plated connector
contacts. There will be internal power supplies for +48VDC, +28VDC,
+13.2VDC, and -12VDC. There will also be a +24VDC line that will be
available regardless of the Power Switch status.
Tape & RTTY Line-Level outputs
will be available, as well as RECORD and Transmit/Receive Switch-Sense-Lines
brought through the unit (with RECORD originating within the unit.) While
individual connector-relay sets will be hard-wired, the relationship between
which relay responds to which switch-closure will be programmable via a
Wire-Wrap matrix, to facilitate logic adaptability, and the rerouting of the
path, should a connector or relay fail.
Other features include a
dot-matrix display of relay-activation status; Bi-color LEDs to indicate
Audio-channel ON (Green-to-Red transition) which provides instant indication
of which channels are on; momentary-up/center-off/on-down mini-lever
switches for all 16 channels of audio switching; 8 position rotary switches
for HF speaker select; VHF/UHF speaker select; and for RTTY destination
(e.g. TU) select. All switching will be designed to "fail-safe-through" to a
safe state during either power-loss or relay failure. All audio signals will
be carried on TFE-shielded cables. Most relays will be 24VDC/28VDC
'crystal-can' MIL-spec (surplus) relays. All relays will have a 1N4001 in
reverse across their coils (except in the case of a 48V relay, which will
get a 1N4002 or better.) The AC line will have a suitable input filter, and
all I/O lines will have at least a ferrite bead.
Finally, all the drawings will
be in Adobe ACROBAT .PDF format. If the resolution fails to be sufficient on
any drawing, just ask. Also, if you see an error, I would greatly appreciate
knowing about it. These drawings are my own except as noted. Please feel
free to reproduce them as long as credit is given to their source.
Once again a reminder:
I am including the AF Controller here
as it is developed, as an
example of Project Design and Implementation. Be
to keep in mind that the
circuits are not final until described as finished!
2001 04 15:
Basic design is
essentially frozen! Final schematics and block diagrams here as finished.
2002 03 28:
Mixer design change...
2002 09 25:
a) Single Channel Switching /
Indicator... b) Mixer design still being worked on...
2002 12 26:
Mixer design change LOOKING GOOD...
continue browsing the website, please select from these categories:
and from an Electronics