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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">It seems to me that this matter is being way over-complicated.</span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt"> </span></span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt">First of all, it is a PERFORMANCE parameter of a circuit block; such as center frequency, Q, or peak
gain, (NOT any particular component value or values) that needs to be fine-tuned.</span><span style="font-size:12pt">
</span><span style="font-size:12pt">Secondly, in order to “correct” a particular parameter or component (actual resistor or capacitor picked out of the parts drawer of nominal conscripts), you have to make a MEASUREMENT (perhaps of an actual component, or likely,
better, of the initial performance parameter). </span></span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt"> </span></span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt">Given these TWO considerations, can we develop a procedure for a systematic and simple near-comprehensive
fix (like one “tweak and done”)?</span><span style="font-size:12pt"> </span><span style="font-size:12pt">Yes we can, and it works extremely well with the filter banks based on the MFIG with positive feedback (“Deliyannis”) bandpass.</span></span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt"></span></span><span style="font-family: Arial, sans-serif; font-size: 12pt;">With such a filter bank,
we absolutely need to get the gains all set quite </span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-family: Arial, sans-serif; font-size: 12pt;">uniformly.</span><span style="font-family: Arial, sans-serif; font-size: 12pt;">
</span><span style="font-family: Arial, sans-serif; font-size: 12pt;">This is essential if we want to use an overall positive feedback</span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-family: Arial, sans-serif; font-size: 12pt;">around the whole bank to simultaneously manipulate the Q of all the </span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-family: Arial, sans-serif; font-size: 12pt;">filters.</span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt">Say we design the nominal peak gains to 1.00.</span><span style="font-size:12pt">
</span><span style="font-size:12pt">We expect any particular instance to have a spread of gains (perhaps 0.97, 1.06, 0.98, etc.). [ Gain is MUCH easier to measure than frequency or Q! ]
</span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span><span style="font-size:12pt">We could imagine a very tedious (and often frustrating) trimming task.</span><span style="font-size:12pt"> </span></span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt"></span><span style="font-size:12pt"> </span></span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt">Instead, suppose we design for a gain of say 0.92 so that we end up with a spread, but with all less
than 1.00. </span><span style="font-size:12pt"> </span><span style="font-size:12pt">In our circuit board, we
</span><i style=""><span style="font-size:12pt">allow</span></i><span style="font-size:12pt"> a space for the addition of a small series resistors added to the lower legs of the feedback divider (temporally we make these wire jumpers). We are looking to have
the original resistor in the lower leg of the divider about 1000 ohms and the “series correction” less than 100 ohms [1] (to be determined – a simple CALCULATION based on the measured (with the jumper) gain.</span><span style="font-size:12pt"> </span></span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:22.0pt; line-height:107%; font-family:"Arial",sans-serif"><span style="font-size:12pt"></span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span><span style="font-size:12pt"> </span></span></p>
<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">The “formula” for the correction comes through the magic of “classical </span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">sensitivity”) [3, 4], with [3] telling exactly how to do the Deliyannis. </span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">References [1] and [2] show my 39 channel filter bank which also </span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">illustrates the method.</span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">Getting all the peak gains the same was our essential goal, but rather </span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">automatically the center frequencies and Q are completely acceptable.</span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">And the tune-up is even fun (under 2 hours for 39 channels) and you get</span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:12pt; line-height:107%; font-family:Arial,sans-serif">to watch the gain settle at 1.00 as the soldered resistors cool!</span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:18.0pt; line-height:107%"><span style="font-size:12pt">[1]</span><span style="font-size:12pt">
</span><span style="font-size:12pt"><a href="http://electronotes.netfirms.com/EN115.PDF" class="OWAAutoLink" previewremoved="true" id="LPlnk364747"><span style="font-size: 12pt;">http://electronotes.netfirms.com/EN115.PDF</span></a><span style="font-size: 12pt;"> </span></span></span></p>
<p class="MsoNormal" style=""><span style="font-size: 12pt;"><span style="font-size: 12pt;">[2] </span><span style="font-size: 12pt;"> </span></span><span style="font-size: 12pt;"><a href="http://electronotes.netfirms.com/EN116.PDF" id="LPlnk826426" class="OWAAutoLink" previewremoved="true" style="font-size: 18pt;"><span style="font-size: 12pt;">http://electronotes.netfirms.com/EN116.PDF</span></a></span><br>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:18.0pt; line-height:107%"><span style="font-size:12pt">[3]</span><span style="font-size:12pt">
</span><a href="http://electronotes.netfirms.com/AN361.pdf" id="LPlnk5242" class="OWAAutoLink" previewremoved="true"><span style="font-size:12pt">http://electronotes.netfirms.com/AN361.pdf</span></a></span></p>
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<p class="MsoNormal" style="font-size: 10pt;"><span style="font-size:18.0pt; line-height:107%"><span style="font-size:12pt">[4]</span><span style="font-size:12pt"> h</span><span style="font-size:12pt"><a href="http://electronotes.netfirms.com/EN196.pdf" id="LPlnk688386" class="OWAAutoLink" previewremoved="true"><span style="font-size: 12pt;">ttp://electronotes.netfirms.com/EN196.pdf</span></a></span></span></p>
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