The pulse generation circuit changes the inputted analog signal into the pulse signal. It inputs the input signal to the inverter and it makes the rectangle wave.
http://www.interq.or.jp/japan/se-inoue/e_ckt9_4.htm
Lilliputian dimensions associated with the submicron geometries of most digital and many analog processes result in much faster circuit operation. As ICs speed up, the rise and fall times of most pulse and function generators, which are typically 5 nsec, become inadequate for measuring time intervals lower than 20 nsec.
http://www.edn.com/contents/images/50301di.pdf
simple device to generate 300 to 4000 Hz test signals
http://www.edn.com/archives/1997/081597/17di_03.htm
produces clean 2mS logic pulses at rate of one per second while drawing only 1 microamp from a 9 volt battery, uses 2 transistor acting as programmable unijunction transistor
http://www.imagineeringezine.com/PDF-FILES/9vpulse.pdf
http://www.evenfall.com/diy/pwm.html
trims the trailing portion of a large-width input pulse to a size as narrow as 10 nsec irrespective of the input-pulse width, circuit doesn't require a capacitor to generate the timing pulse
http://www.edn.com/archives/1997/030397/05DI_07.htm
A marx generator is described as a device which uses a network of resistors, capacitors, and spark gaps to produce a brief, ultra-high power electrical impulse.
http://home.earthlink.net/~jimlux/hv/marx.htm