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authorWerner Almesberger <werner@almesberger.net>2015-03-13 13:18:57 -0300
committerWerner Almesberger <werner@almesberger.net>2015-03-13 13:18:57 -0300
commit4db9b55fd5373f8ab4331fef430bf7bcc7ded8ce (patch)
treebd5be616fb54888f2678fd34762ddb42a99746b0 /ir
parent55e2604f9cf7145d3aa4456658260ace68bc260c (diff)
downloadmisc-4db9b55fd5373f8ab4331fef430bf7bcc7ded8ce.tar.gz
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ir/: thicken hysteresis arrows; some small text improvements
Diffstat (limited to 'ir')
-rw-r--r--ir/filter.fig20
-rw-r--r--ir/ir.tex9
2 files changed, 15 insertions, 14 deletions
diff --git a/ir/filter.fig b/ir/filter.fig
index dddf116..4a6a5d6 100644
--- a/ir/filter.fig
+++ b/ir/filter.fig
@@ -25,12 +25,6 @@ Single
9675 6210 10215 6210
2 2 0 3 0 7 50 -1 -1 0.000 0 0 7 0 0 5
5310 5985 5940 5985 5940 6435 5310 6435 5310 5985
-2 1 0 2 0 7 50 -1 -1 0.000 0 0 7 1 0 2
- 1 1 2.00 30.00 22.50
- 5535 5760 5580 5895
-2 1 0 2 0 7 50 -1 -1 0.000 0 0 7 1 0 2
- 1 1 2.00 30.00 22.50
- 5625 5760 5670 5895
2 1 0 3 0 7 50 -1 -1 0.000 0 0 -1 1 0 2
0 0 3.00 150.00 150.00
6525 6210 6525 6975
@@ -42,12 +36,18 @@ Single
2 1 0 3 0 7 50 -1 -1 0.000 0 0 -1 1 0 3
0 0 3.00 150.00 150.00
10125 7200 9135 7200 9135 6525
+2 1 0 2 0 7 50 -1 -1 0.000 0 0 7 1 0 2
+ 1 1 2.00 30.00 22.50
+ 5535 5760 5580 5895
+2 1 0 2 0 7 50 -1 -1 0.000 0 0 7 1 0 2
+ 1 1 2.00 30.00 22.50
+ 5625 5760 5670 5895
2 1 0 2 0 7 40 -1 -1 0.000 0 0 -1 1 0 2
- 1 1 2.00 30.00 30.00
- 8910 6390 9000 6210
-2 1 0 2 0 7 40 -1 -1 0.000 0 0 -1 1 0 2
- 1 1 2.00 30.00 30.00
+ 1 1 2.00 45.00 45.00
9000 6030 8910 6210
+2 1 0 2 0 7 40 -1 -1 0.000 0 0 -1 1 0 2
+ 1 1 2.00 45.00 45.00
+ 8910 6390 9000 6210
3 2 0 2 0 7 50 -1 -1 0.000 0 0 0 3
7409 6383 7544 6068 7724 6023
0.000 -1.000 0.000
diff --git a/ir/ir.tex b/ir/ir.tex
index d53f6bc..0092c41 100644
--- a/ir/ir.tex
+++ b/ir/ir.tex
@@ -689,11 +689,11 @@ The following diagram shows the IR receiver circuit:
\includegraphics[scale=0.89]{rx.pdf}
\end{center}
-When the receiver is enabled (analog switch U1 is closed), D1 is
+When the receiver is enabled (analog switch U2 is closed), D1 is
reverse-biased through R6.
-R6 pulls the signal {\bf B} close to ground when the diode is not
+R6 pulls the signal at {\bf B} close to ground when the diode is not
illuminated, and lets the voltage raise when D1 is illuminated and
-the current through it increases.
+the reverse current through it increases.
The high-pass filter is implemented by comparing the signal from the
sensor ({\bf B} and {\bf C}) with the same signal after passing the
@@ -706,7 +706,8 @@ signal detection.
The comparator U1 operates as inverting Schmitt-trigger, with
R1 and R2 determining the hysteresis.
-When the receiver is disabled and the sensor is not illuminated,
+When the receiver is disabled (analog switch U2 is open) and the
+sensor is not illuminated,
the voltage divider formed by R3 and R4 (with some contribution
from R1) lets C1 charge to the expected operating point.
R6 pulls {\bf C} to ground in this case.