How to Design 12V Automotive Circuit for 20ms Pulse Output from 1s Square Wave Input?

need help to design circuit that produce single pulse as output about 20 ms but input signal
is about 1 sec.Automotive application 12-14 v and input is power signal square wave.Please help or give general idea.

Good ol' 555 timer might do the trick. You don't say whether the 20ms pulse needs to occur on the rising or falling edge of the 1 sec "signal". Also, is this "1 sec signal" also a square wave or something else. If something else, then might need a Schmidt trigger input or comparator. Also is it 12-14v or something else? If something else, then other signal conditioning might be needed. Also, how precise does the timing need to be. "20ms" implies 2-sigfig precision. Is that correct? Also, is this input signal noisy? Might need some filtering on the input. If so, how soon after the edge does the 20ms pulse need to occur?

O.K.Trigger input (10-14 v DC from MOSFIT) duration is 1.0 sec ,pattern-square wave w/o noise.
Output signal: square wave DC able to drive 12.0 v mechanical relay with more than 200 mA load.
Duration 20 to 50 ms will be OK.Output have to be occur as soon as possible on
rising edge of input signal.
P.S.I have no any education in electronics and this is my own progect because no electronic units are
longer avalable as OEM parts for my old Nissan.But I'am nissan master technician.
Thank you very much Steve for your respect and help !

Try the attached. I haven't tested this so no guarantees.

Sorry Steve ? If any components could have variable value in case need to change output signal duration and that the formula if that possible.

R2 and C2 are the frequency determining components. Here's the formula:

Time = 1/2*R2*C2 where Time is in 'ms', R2 is in 'K', and C2 is 'uf'. Example: Time = 0.5(470K)(0.1uf) = 23.5ms

Here's a link to a couple of data sheets for the CD4098B (the Intersil datasheet is easier to read, but I included TI because Mouser and Digi-Key only have the Texas Instruments part--they're compatible):

http://www.intersil.com/data/fn/fn3332.pdf
http://www.ti.com/lit/ds/symlink/cd4098b.pdf

Mouser Part #: 595-CD4098BE
Digi-Key Part #: 296-3526-5-ND

In fact, here's a BOM (for Mouser.com 'cuz they are a little more "Beginner Friendly"):
Go To : www.mouser.com and purchase these parts:
D1: 1N4744A -- Part #: 512-1N4744A
D2: 1N4004 -- Part #: 863-1N4004RLG
IC1: CD4098B -- Part #: 595-CD4098BE
Q1: ZVN4306A -- Part #: 522-ZVN4306A Datasheet: http://www.diodes.com/datasheets/ZVN4306A.pdf
R1: 15K -- Part #: 271-15K-RC
R2: 470K -- Part #: 271-470K-RC
R2-Alt: 698K -- Part #: 271-698K-RC
C1: 0.01uf -- Part #: 594-K103K15X7RF5TL2
C2: 0.1uf -- Part #: 81-RHDL82A104K2K1C3B
D1: 1N4744 -- Part #: 512-1N4744A
CN1: TermBlock -- Part #: 845-34.103

The "R2-Alt" is an alternate selection for R2 which theoretically puts the timing at 35ms which is in the middle of the range you specified. That provides plenty of leeway for error. Get both and use the one that works the best. If you want you could get more values, just go to Mouser.com and search on one of the part numbers (such as 271-698K-RC), then select one of the listed entries and then find the "Show Similar" button down below the specifications list. That should take you to a parametric search tool where you can select different values.

An alternative method would be to put a trim pot (Part #: 774-201XR105B ) in series with a 100K resistor, then adjust it to optimal operation. But, don't use the trim pot in the actual design. Measure it's resistance and then order a resistor at the closest value available.

*Correction:* In the method where you use a Trim Pot to determine the optimal value: measure the Trim Pot and add 100K, or measure the resistance of the Trim Pot and 100K resistor in series.

Thank you very much again.I have ordered comps from Digi-Key and wating them ASAP I will assembly device and let you now how It's working.
German.

Hello Steve.I've assembled the circuit.Something wrong.I've to use 9.0V battery as a power and mini automotive relay 10.0 V 40 mA .Then power and ground are completed RL1 is energized immediately.Nothing happen than signal (IN) is applied from tactile momentary switch (signal is same source but momentary ) .Nothing happen also if IC terminal 10 and 12 are disconnected.At terminal 12 about 0.6 V is present all the time nevertheless if SW is pressed or not.I have changed IC and MOSFET w/o any success. The MOSFET was connected as S to RL1 coil,D to the ground and G to IC's 10 and 12.If you have any idea that need to try please let me now.
Thank you,
Guerman
P.S. all components have been used exact same as in your circuit.

You have the MOSFET backwards. S goes to ground and D to the relay. Also, make sure that the input line to pin 11 is low when the momentary switch is NOT press and goes high when it is pressed.

Let me know what happens.

Hello Steve I have installed MOSFET as you told.Now then I initialy supply power and ground to the circuit my lamp(I've installed instead relay) flushes once and nothing happen then momentary switch is pressed.But sometime then than terminal 11 is disconnected and power and ground is applied to circuit lamp blinks momentary and after 2 sec goes ON stays about 20 sec and goes OFF. After that it goes ON again but stays ON and never goes OFF.The voltage on 11 is about 37 mV then switch is OFF and I have batt.voltage if svitch ON.Please tell what do you think.
Thank you,
Guerman

I attached a new diagram and marked in red what changed. Try that and let me know what happens.