Dear Yves,
Thank you for the comparative measurement, showing noise from the 8657B in RF Off being 4.6 dB above thermal noise.
The difference I measured is somewhat less, because I did not correct for the receiver noise figure.
To complete the comparison, could you check the level with the 8657B mains switched off?
If this is a feature, these signal generators cannot conveniently be used to measure the sensitivity of low noise receivers.
I will check my other signal generators- I know that the 8643A does not show the same issue.
Anyone else noticed this?
Also, does anyone know why this noise is being produced?
I will check whether it is attenuator setting dependent.
Regards,
Alwyn
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Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.
SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
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