E
Eeyore
- Jan 1, 1970
- 0
The strain gauge thread reminded me of a product with an 'issue' I was once
asked to take a look at.
It was the receiver section of a marine radar.
The detector was followed by several variable gain stages. These were wideband
IC amplifiers made by Ferranti ( now Zetex ) with a control current / voltage
that varied each IC's gain over about something like a 12-15dB range. The
control ports were driven in parallel so that gain was swept equally between all
the devices.
They were at least 6 of these cascaded to provide the necessary gain before the
signal went off for further processing.
After the pulse was transmitted ( and the receiver input clamped ) the gain was
ramped up with a triangle waveform to provide the necessary low gain for near
targets and higher gain for distant targets.
I took one look at the schematic, grinned and said I could fix it.
What problems ( not less than 2 of them ) were they encountering ?
Graham
asked to take a look at.
It was the receiver section of a marine radar.
The detector was followed by several variable gain stages. These were wideband
IC amplifiers made by Ferranti ( now Zetex ) with a control current / voltage
that varied each IC's gain over about something like a 12-15dB range. The
control ports were driven in parallel so that gain was swept equally between all
the devices.
They were at least 6 of these cascaded to provide the necessary gain before the
signal went off for further processing.
After the pulse was transmitted ( and the receiver input clamped ) the gain was
ramped up with a triangle waveform to provide the necessary low gain for near
targets and higher gain for distant targets.
I took one look at the schematic, grinned and said I could fix it.
What problems ( not less than 2 of them ) were they encountering ?
Graham