SA612 external oscillator how to?

[neazoi]

Hi,
This page https://www.qsl.net/g3oou/activemixers.html explains how should an external oscillator could be connected to the SA612.
Is there anything else I need to consider/know?

 

[D.A.(Tony)Stewart]

Do you mean external crystal ? or clock? It expects a certain level ac coupled with internal self bias, but not specified

Why external osc?
What stability do you need ? 100ppm? 1ppm?

I suspect ideal input is around 1Vpp sinewave to Base input but not using a crystal with internal feedback loop adds mixer performance uncertainty. Use coax with 47 Ohm and cap from low impedance source.

Specs say

• 
  [*=left]If an external oscillator is to be used then the 47ohm resistor is provided to ensure that the NE602 internal oscillator is prevented from operating. Users should ensure that this is the case. External injection should be at least 200mV pk-pk.

 

[neazoi]

Do you mean external crystal ? or clock? It expects a certain level ac coupled with internal self bias, but not specified

Why external osc?
What stability do you need ? 100ppm? 1ppm?

I suspect ideal input is around 1Vpp sinewave to Base input but not using a crystal with internal feedback loop adds mixer performance uncertainty. Use coax with 47 Ohm and cap from low impedance source.

Specs say

• 
  [*=left]If an external oscillator is to be used then the 47ohm resistor is provided to ensure that the NE602 internal oscillator is prevented from operating. Users should ensure that this is the case. External injection should be at least 200mV pk-pk.

I thought of using 2 of these as an IQ mixer, but I think I am going to better use a switching mixer better

 

[betwixt]

Do you mean SA602 or SA612?

The 612 explains the different internal oscillator configurations in the Philips data sheet figure 7.

Brian.

 

[neazoi]

Do you mean SA602 or SA612?

The 612 explains the different internal oscillator configurations in the Philips data sheet figure 7.

Brian.

I would better use the sa612, as it is better.