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#1
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uae of mimic citcuits as post mixer amps.
Anyone had experience of using mimic's as post diode balanced mixer
amplifiers? In theory they look OK, 50 Ohms in and out and good high level signal handling. This is to be for a 45 MHz first IF. Cliff Wright ZL1BDA |
#2
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uae of mimic citcuits as post mixer amps.
clifford wright wrote in
: Anyone had experience of using mimic's as post diode balanced mixer amplifiers? In theory they look OK, 50 Ohms in and out and good high level signal handling. This is to be for a 45 MHz first IF. Cliff Wright ZL1BDA Assuming you have a decent filter after the mixer to extract the band you want, the MMIC amps work fine. However, I'd be wary of any recent Avago parts. The data sheets can be very inaccurate, and the parts may not behave as advertised. I've had very good luck with NEC, and a lot of MiniCircuits amps are decent as well. RFMD also has some nice parts. The Avago parts that were actually designed when they were Agilent (or better yet HP) are also good. If the parts are advertised as 50 Ohms in & 50 Ohms out, there is a lot less to go wrong. The ones that require custom matching networks take more care to get running right because of circuit & component parasitics. Doug White |
#3
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uae of mimic citcuits as post mixer amps.
On 11-12-2011 13:29, Doug White wrote:
clifford wrote in : Anyone had experience of using mimic's as post diode balanced mixer amplifiers? In theory they look OK, 50 Ohms in and out and good high level signal handling. This is to be for a 45 MHz first IF. Cliff Wright ZL1BDA Assuming you have a decent filter after the mixer to extract the band you want, the MMIC amps work fine. However, I'd be wary of any recent Avago parts. The data sheets can be very inaccurate, and the parts may not behave as advertised. I've had very good luck with NEC, and a lot of MiniCircuits amps are decent as well. RFMD also has some nice parts. The Avago parts that were actually designed when they were Agilent (or better yet HP) are also good. If the parts are advertised as 50 Ohms in& 50 Ohms out, there is a lot less to go wrong. The ones that require custom matching networks take more care to get running right because of circuit& component parasitics. Doug White When using the MiniCircuit MMICs, I recommend using the "optional" choke between the device and its biasing resistor (as shown on device datasheets). Without it, you can lose a few dB of gain. The value is not critical. At 45 MHz, 5 or 6 turns through a VHF ferrite bead should be enough. The MAR-4 is a decent choice unless you need more gain or output level. The datasheets show gain and max power out (P1dB)...if you want it to be linear, stay below that point. If you know the level at 45 MHz and the level you want out of the MMIC, you can place a simple resistive PI or T attenuator between your 45 MHz source and the MMIC, then the output of the MMIC would be the level arriving at the MMIC plus it's associated gain. http://www.minicircuits.com N0EDV |
#4
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uae of mimic citcuits as post mixer amps.
On Nov 12, 2:01*pm, clifford wright
wrote: Anyone had experience of using mimic's as post diode balanced mixer amplifiers? In theory they look OK, 50 Ohms in and out and good high level signal handling. This is to be for a 45 MHz first IF. Cliff Wright ZL1BDA Hello. I'm succesfully use M/A-COM MAAMSS0017 and MCL GALI-6F. Very important element is a 2 dB attenuator (for example, "T" of 5.6, 220 and 5.6 OHms) before XTAL filters. |
#5
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uae of mimic citcuits as post mixer amps.
you can place a simple
resistive PI or T attenuator between your 45 MHz source and the MMIC, then the output of the MMIC would be the level arriving at the MMIC plus it's associated gain.http://www.minicircuits.com Is a bad idea... attenuatr before MMIC increase NF receiever. |
#6
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uae of mimic citcuits as post mixer amps.
*If you know the level
at 45 MHz and the level you want out of the MMIC, you can place a simple resistive PI or T attenuator between your 45 MHz source and the MMIC, then the output of the MMIC would be the level arriving at the MMIC plus it's associated gain.http://www.minicircuits.com N0EDV Is a bad idea. Atttenuation before MMIC invrease NF of receiever. |
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