window comparator using only one op-amp

I know how to design a comparator, but what is a /window/ comparator?
Lee wrote:

A "comparitor" that compares for a voltage that is within a "window" between X and Y. If the voltage is inbetween, the output is "true", otherwise "false". It's generally done using two comparitors, often with a wired *or* at the output. In it's simplest form:
| | .-. .-. | | | | | | | | |\| '-' '-' IN o-----+-----|-\ | | | | >------+------o Out Y |-------------|-----|+/ O.C. | .-. | |/| | | | | | | | | | '-' | |\| | X |-------------|-----|-\ | .-. | | >------+ | | +-----|+/ O.C. | | |/| '-' |
The output will be high if the input voltage is between X and Y.
created by Andy´s ASCII-Circuit v1.22.310103 Beta