[Fwd: LF: DDS Board Progress]

[Andre' Kesteloot]

Talbot Andrew wrote:

> The AD9850 DDS Board is now with the PCB manufacturers.  I went there
> yesterday to check the solder mask, and had a fascinating trip round the
> factory looking at PCB manufacture and SMT component pick and place
> mounting.  Delivery is still quoted as 30 days so we have about 3 - 4
> weeks left as these are being batched with other PCBs.
>
> Price of the PCB will probably be £8.00, plus p&p whatever that will
> come out at.  HF Instruments will also coordinate a bulk purchase of
> AD9850 chips and some AD9851 devices too (see below), prices still to be
> fixed.   I have also been told that it will be possible to supply chips
> mounted on the PCB for those frightened by the thought of soldering 28
> 0.65mm spaced pins - although its not as difficult as you might think
> especially with a solder mask there to help avoid shorts underneath.
>
> The AD9851 DDS chip is pin compatible with the AD9850 device and has an
> internal x6 clock multiplier allowing it to be used with up to a 30 MHz
> oscillator to give a clock freqeuncy to 180 MHz - output range can then
> go from DC to 70 MHz in steps of 0.04 Hz.   For LF use however, I would
> still recommend the AD9850 device with a drive frequency of 4 - 5 MHz
> giving mHz steps.
> One interesting aspect that comes out of the 9851 data sheet is the use
> of the aliassed DDS products, after bandPASS filtering, to generate
> frequencies in the VHF range up to 100s of MHz.   Very useful to
> microwavers.
>
> Andy  G4JNT
>
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