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If you are using a Minicircuits ZAD-6 level 7 mixer then it should give about 35dB port isolation from LO to IF at 70MHz and a bit less at 140MHz.
So with +7dBm LO you would normally get about -28dBm LO power leaking to the IF port from the 70MHz LO port. You will also get some leakage at...
When measuring harmonics with an analyser you are supposed to follow a basic rule of thumb where the internally generated harmonics (in the analyser) should be about 15dB lower than the harmonic level you are measuring. Otherwise you can get significant measurement uncertainty due to the...
One way you could do it on an old/basic VNA (i.e one without group delay capability) would be to extract s parameter data into a PC for both cases across a wide frequency range and then post process the data in the PC to predict (or reverse engineer) the total delay time for each microstrip line...
I don't know what your design requirements are so I can't say if your layer stack is the ideal choice or not. Normally, I would choose 0.020" Rogers 4003 up at several GHz because the metal losses are lower than for 0.008".
Also, I don't know how big your PCB is. Normally, I work alongside a...
The quick and easy way to do it for any simulator is to simply make a 1 port model in a text file as below.
# MHZ S MA R 50
0.01 1 90
10000 1 90
This linear 1 port s parameter model gives a constant reactance of 50 ohms from 10kHz through to 10GHz (i.e. it has a constant 90deg phase angle for...
I've made lots of designs using Rogers + FR4 stackups and I've always been advised to make the layer stack symmetrical or the board can warp. So a typical design might be 0.020" Rogers on layer 1 then a 4 layer FR4 core and then another 0.020" Rogers layer on the bottom layer. Some designs use...
I suppose you could make/borrow a dual directional coupler and use a modern two channel digital scope and a signal generator (with low harmonic content) if the SAW frequency is within the range of the scope.
If you have access to a decent two channel digital scope you could use the scope maths...
If you use a bridge rectifier in the PSU then the ripple will be most significant at 100Hz rather than 50Hz.
Also, with some types of linear regulator you need to be careful of adding smoothing capacitors everywhere because you can cause 'big' transients on the PSU output with step changes in...
Yes, that's pretty much the same classic 4:1 TLT based circuit I posted up earlier but the circuit in your link is configured for much higher gain.
I'd expect it to show more than 20dB gain and presumably it will require a more careful layout to prevent possible instability up at VHF and UHF. I...
The 4:1 TLT is 4:1 impedance
Wind it as per fig 4C in the link below (i.e. the 4:1 transmission line transformer)
You have to be careful how you strap the two windings together and the image in the link below shows it quite well.
The 4Zo connection goes to the collector of the transistor...
Here's a screenshot of the CATV amplifier design.
You can see it has about 15dB gain across 2MHz to 30MHz and K>1 and B1>0 for stability.
You can also see it has good input and output match for a 50R system and should also produce +10dBm with harmonics much lower than -40dBc. But this is just...
I'm tempted to be boring and just post up a classic circuit of a CATV based design using a 4:1 TLT and feedback to produce a broadband amp with very well controlled 50R input and output but here's a quick and dirty tuned version for 7MHz that should have +15dB gain and 50R input and output at...
Don't take this the wrong way but I also think you may need to reconsider your choice of project. IMO your project should ideally satisfy a valid requirement. In 2012 I don't think basic FM modulator is a good choice. It was maybe a VERY good choice 20-30 years ago especially if it was designed...
Whoops, I just realised you are intending to use the VCO inside the 4046 and pick out a harmonic. (I thought you were just using the phase detector section of this chip)
Using the 4046 VCO is a bad idea for lots of reasons. One reason is that each time you multiply by 2 you degrade the phase...
Answers:
1. Good frequency accuracy and stability over time and temperature and ease of tuning across multiple channels.
2. Yes you can use the 4046. Consider which phase detector you are going to use within the device and if you want to use an active LPF after it. However, see answer 3 below...
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