[hpsdr] hOw AbOuT a PiNG?

[Ahti Aintila]

On 17/04/07, Gerd Loch <g.loch at nt-electronics.de> wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> in relation to which schematic are the results of the QSD?
> 73 Gerd, DJ8AY

Gerd,
I have only the TINA simulation diagram (small enough for an
attachment), if you mean the excellent measurement results of Marco,
IK1ODO:
I'm still working on it, with the aim of improving the behaviour at 50 MHz.
So far I have sensitivities (noise floor in 2.4kHz BW) of around -123
dBm (50MHz), -127dBm (28MHz), -130dBm (7MHz).
The two-tone dynamic range arrived at 108dB in 14 MHz (quite
difficult to measure), and the 3rd order IP is +35dBm.
--
I recently modified the circuit to have 180° conduction angles on the
switches, as suggested by Ahti. The improvement is small, but
measurable; however, the input impedance matching is a little worse
(after having changed all circuit values and rewound four different
input transformers).

I received an E-MU 1616m just saturday, and will do some more work on
in in next weeks. I would say that the IQSD is ok, the improvements
will be marginal now; we need an LO to go with it. AD announced the
AD9912 - 1 GHz 14 dds with spurious cancellation. Who will be the
first to try it?

73 - Marco IK1ODO
--
If you have the TINA software installed, I can send you the TSC-file.

Marco has the original circuit diagram, but he is still working with
some impedance matching details of that, so better wait for the
final(?) results from him.

73, Ahti OH2RZ

>
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