I'm new to this list, so please forgive me if I am missing some older
information not in your post.
I also believe you are overdriving the amplifier, but the oscilloscope
display scaling is confusing us. Several things stand out at me from
your message:
* The AD9858 has a current-mode D/A
The DDS puts out perhaps a volt far to large for a preamp device. I suspect
like everyone else you are clipping. Just take a 2n3904 use it as a common
collector/buffer and bias the emitter for a clean cycle and see what level
you get.
Regrads
Paul
WB8TSL
On Sat, Jan 17, 2015 at 2:51 AM, Tom
Hello,
That Q1 is MAV1-0104 made by Mini-Circuits. This part is exact
replacement for the MSA-0104, which was in TenTec kits early.
The schematic of that pre-amp is pretty simple:
+12 V
|
[ ] (470 Ohm)
Hi
The amp you are using has about 18.5 db of gain. It’s a typical self biased
transistor style amp. From the part number, it’s got a ~ 1.5 dbm output limit
at 1 db compression. That gives you a max input level of -17 dbm when the amp
is in compression. If you want reasonable noise
Hi,
I am not clear about the little sawtooth riding on the signal, but it
looks like you are running out of headroom on the Ten-Tec preamp. The
Ten-Tec preamp would not be my first choice for the job. One of the
Minicircuits MMIC's would probably be a better choice depending upon
your
- Original Message -
From: d0ct0r t...@patoka.org
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Saturday, January 17, 2015 12:02 AM
Subject: [time-nuts] DDS on AD9852
Hello,
I would like to ask some advise about the signal distortion I get
