Recent content by Wapochief

Thanks, I spent the day reading and studying this and I am closer to understanding. I'll post back if I have any more questions.

Hi Bobbywhy, So suppose I only have one TX and one RX antenna - both stationary, near each other and pointed in the same direction. From my understanding, the steering vectors are just 1 for each. But how do I get the angle of the target? I am trying to create an Angle/Range map. Thanks

Hey all, I am brand new to the world of signal processing and radar, but I am trying to simulate a non-doppler imaging radar using pulses. I understand most of the concepts, including steering vectors and measuring distance by the time delay of a radar pulse. I am using a stationary antenna...

Gigaohm or 10^9 ohms =P

Even a Gohm works if you don't use flux.

Get a small tip, and put the solder on the tip. Hold the resistor down, then touch the solder tip to one end. Should flow across. Used a 1/32" tip at 350 degrees f.

Just an 0805 100mohm surface mount resistor. No flux to avoid lowering the resistance. Didnt even cut out the pcb.

Just wanted to let you know the project worked like a charm! Couldn't have done it without you. We ended up using the OPA656, with a 100Mohm and a 0.2 pF capacitor. Ideally the capacitor should have been smaller to get better BW, but I couldn't find any. It was decided a gain of 10^8 was enough...

When I calculate c2 in MT-059, I get a very small capacitance (2*10^-14 f). According to MT-059, if I increase the capacitance, it increases the stability - makes sense since it dampens the gain. So I seem to be stable if I use my 0.13 pf for a linear amplification range. In order to keep the...

I am still not sure how to calculate the effect of source capacitance. I read the MT-050 from Analog Devices, but it still does not make sense. Do you know of any other good resource for this?

Have not had a chance to hook this up to the real source, but doing the calculation here: http://www.analog.com/static/imported-files/tutorials/MT-059.pdf It does not seem like the 200pf is a big deal. The feedback cap still needs to be very small... 0.0025 pf with a 100Mohm feedback resistor...

I am not sure how to measure the capacitance, since it is so small... We are using +/-4 and +/-15 volts supply, and the output is only 1v maximum(with 10nA input). I would assume neither is high voltage.

Any idea where I can get a variable cap that small? (0.1 pf or less) The customer does not like the wire wrap. Couldn't find anything below 0.25 pf and I need around 0.1 pf.

The 100MOhm resistor worked, with the wire wrap I am seeing over 200khz of bandwidth. The noise floor is -70db, and amplifying it by 10 will make it about -50db - not what I need, but close. Overall a good success. Thanks for your help.

That would work, but we would need very good linearity. Seems like I would need a LOT of amplifiers to make a difference. The latest link has 30Hz BW.