N1mhc@arrl.net
Al sirois
East Boothbay, ME
-----Original Message-----
From: Henry, John [mailto:jhenry@tentec.com]
Sent: Friday, October 01, 2010 8:59 AM
To: Discussion of Ten-Tec Equipment
Subject: [TenTec] Eagle A few answers
The DSP used in the Eagle is the ADSP21261 SHARC DSP, a 32bit DSP with
40bit floating point math, operates at 150MHz up to 900MFLOPS peak for
some operations. The AKM4683 codec is 24bits. Plenty of horsepower
and bits for what is needed for this feature level transceiver.
A PIC chip is used for front panel controls, communications, overall
system hardware control, etc, leaving all of the real audio processing
performed by the DSP.
VFO A and VFO B frequency and mode are remembered per band.
The bandwidth and step size are remembered per mode.
VFO B really only is a retainer place for a frequency, it follows the
same mode/bandwidth as the main VFO does.
When operating split, VFO B is always the transmit VFO, allowing you
to have an offset frequency for transmit, it uses the same mode and
bandwidth when swapped back to receive in VFO A and it will still use
the same mode as in VFO A for transmit. Cross modeing is not available
in the Eagle but it is available in the OMNI-VII and Orion series.
The transmit bandwidth is always fixed, e.g. for CW or SB it will
always be the 2.4kHz filter, for AM it will always be the optional
6kHz filter, and for FM it will always be the optional 12kHz filter,
regardless of what you have the receive bandwidth set for. The
transmit bandwidth in DSP is not adjustable either, it is always the
same 2.4kHz, 6kHz, 12kHz scheme as above.
Like the OMNI-VII, you can select any DSP bandwidth for any mode, up
to and including the largest filter you have installed. You may ask
"who needs 300Hz in SB", well, when using it in some digital modes,
this is actually a very useful combination, switch to a very low DSP
bandwidth, maybe adjust pbt if required, and knock out a lot of noise.
As in the OMNI-VII, it has a single physical synthesizer, meaning it
can only receive one signal at a time, its not a dual receiver, but it
is a dual VFO so that you can transmit xhz up or down from the rx
frequency.
AM, You can always turn on AM mode, regardless of whether you have the
6kHz filter installed or not. However you cannot transmit AM unless
you have the 6kHz filter installed.
The same for FM, can listen at any bandwidth, even 300Hz (makes no
sense, but you can), but you can't transmit unless you have the 12kHz
filter installed.
I'm sure the above will generate more questions, but that is what
these boards are for.
Thanks,
John Henry
TenTec Engineering
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