Hawaslsh
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Hello,
Had a question about whether or not I need concern myself with impedance matching. The circuit above is pretty standard: filter a down converted IF and amplify for further processing. The IF is ~30 MHz, the mixer (SYM-2500+) i can only assume is matched to 50 Ohms. The LPF are series LC circuits designed for 50 Ohm terminations. Since its a low enough frequency, I was going to use a low noise op-amp in a non-inverting topology, feeding directly to the positive input of the amp.
I realize i just said it was low enough frequency, but should I be concerned about filter and mixer not seeing a 50 ohm termination at the input of the amp? At 30 MHz, is the infinite impedance of the amp even going to matter?
Im going to see what LT-spice says, but just wanted a second opinion or three.
Thanks in advance,
Sami
Had a question about whether or not I need concern myself with impedance matching. The circuit above is pretty standard: filter a down converted IF and amplify for further processing. The IF is ~30 MHz, the mixer (SYM-2500+) i can only assume is matched to 50 Ohms. The LPF are series LC circuits designed for 50 Ohm terminations. Since its a low enough frequency, I was going to use a low noise op-amp in a non-inverting topology, feeding directly to the positive input of the amp.
I realize i just said it was low enough frequency, but should I be concerned about filter and mixer not seeing a 50 ohm termination at the input of the amp? At 30 MHz, is the infinite impedance of the amp even going to matter?
Im going to see what LT-spice says, but just wanted a second opinion or three.
Thanks in advance,
Sami