Right. A separate dual-channel arbitrary waveform generator makes the baseband I/Q signals to simulate metal things flying past the sensor.
The latest idea is to use two AD835 linear multipliers, one for I and one for Q. Both get the RF carrier, one straight in and one shifted 90 degrees. Each also gets a baseband signal from the dual-channel waveform generator. The multiplier outputs are then summed to be the simulated sensor output.
The AD835 is pretty nice. Z = X*Y, 4 quadrant, all scaled to 1 volt.
If I can make the box general enough, I can make it the customer's problem to work out all the details.
(I'm waiting for the temp to get up enough to go skiing. It hit 6F at
7AM and is warming up slowly. I don't like to ski below 20F maybe.)
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John Larkin Highland Technology, Inc
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
If John had gone to AoE 2 or 3 he might have found the standard 90 degree single pole all pass filter - figure 6.41 in AoE 3.
It goes from 0 degrees to 180 degrees over the zero to infinity frequency range, hitting 90 degrees at the design centre frequency. You could do it with a current feed-back amplifier, but the phase shifting resistor can't be large.
The AD8000 wants to see 50R to ground at the non-inverting input, which would make the capacitor 216pF - 212pF with a more practical 51R resistor.
ee single pole all pass filter - figure 6.41 in AoE 3.
cy range, hitting 90 degrees at the design centre frequency. You could do i t with a current feed-back amplifier, but the phase shifting resistor can't be large.
would make the capacitor 216pF - 212pF with a more practical 51R resistor.
AoE is a great text book, but it told me very little that I hadn't known be fore I came across it. Cambridge University used it as an undergraduate tex t, and I'd been working at Cambridge Instruments as a senior engineer when it started showing up on the desks of the junior engineers. I asked about i t, looked into it and liked what I saw well enough to buy a copy for myself . It is a handy and well-indexed reference book, but I'd been formed as an electronic engineer rather earlier by what I could dig out of university li braries (which is still rather a more comprehensive source than what's now easily accessible over the internet).
AoE and and the internet are both very handy, but I do pre-date them both, and can't blame either of them for the way I've turned out. You would be ra ther more in need of something to blame - drinking unpasteurised milk is st upid, but it looks as if you've had other - equally foolish - ideas which m ay have done you even more damage.
rather earlier by what I could dig out of university libraries (which is still rather a more comprehensive source than what's now easily accessible over the internet).
degree single pole all pass filter - figure 6.41 in AoE 3.
quency range, hitting 90 degrees at the design centre frequency. You could do it with a current feed-back amplifier, but the phase shifting resistor c an't be large.
hich would make the capacitor 216pF - 212pF with a more practical 51R resis tor.
n before I came across it. Cambridge University used it as an undergraduate text, and I'd been working at Cambridge Instruments as a senior engineer w hen it started showing up on the desks of the junior engineers. I asked abo ut it, looked into it and liked what I saw well enough to buy a copy for my self. It is a handy and well-indexed reference book, but I'd been formed as an electronic engineer rather earlier by what I could dig out of universit y libraries (which is still rather a more comprehensive source than what's now easily accessible over the internet).
th, and can't blame either of them for the way I've turned out. You would b e rather more in need of something to blame - drinking unpasteurised milk i s stupid, but it looks as if you've had other - equally foolish - ideas whi ch may have done you even more damage.
Sadly for Jamie, it's not the record that is broken, but the equipment bein g used by Jamie to play the record. He switches off when his own short-comi ngs come up for review.
m both, and can't blame either of them for the way I've turned out. You wou ld be rather more in need of something to blame - drinking unpasteurised mi lk is stupid, but it looks as if you've had other - equally foolish - ideas which may have done you even more damage.
being used by Jamie to play the record. He switches off when his own short- comings come up for review.
If you knew the correct contraction for Doctor of Philosophy - which is Ph. D. - you comment might have been less self-defeating.
We do keep reminding you that your own output isn't entirely suitable for p ublic exhibition, but this hasn't improved your sphincter control. Then aga in, you don't seem to be able tell shit from shinola.
them both, and can't blame either of them for the way I've turned out. You would be rather more in need of something to blame - drinking unpasteurise d milk is stupid, but it looks as if you've had other - equally foolish - i deas which may have done you even more damage.
ent being used by Jamie to play the record. He switches off when his own sh ort-comings come up for review.
o
Ph.D. - you comment might have been less self-defeating.
or public exhibition, but this hasn't improved your sphincter control. Then again, you don't seem to be able tell shit from shinola.
But how would Jamie know? We know that he thinks he knows - but his opinion is clearly worthless.
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