Hi Hiten09,
Sorry, it is not clear yet what exactly you are looking for.
If you send a continuous 38KHz, you get at pin1 of RX1 a continuous low voltage (RX1 output, when on, sinks current).
When 38KHz signal is off, you likely get at pin1 a high voltage (by using a pull up resistor as R2 if connected to 5V) and random short pulses (to ground) because of noise/interference.
The node of this pin1 (connected to the MCU Vcc via a pull-up resistor, about 4K7) could be connected to an MCU pin (better if it is an interrupt pin). The role of the MCU would be then to measure the time between two falling edges for example (as it is the case for my Atmel C51 MCUs) and decide when it is valid. Actually more than one time interval are measured to be sure the received pattern is valid. The pattern of the IR pulses carried on the 38KHz could be very simple (same period) or complex like a series of 0 and 1 bits (0 could be a short period interval and 1 a relatively long one, say twice). Also a starting long pulse could be added prior of a data packet that is formed by 32 bits for example. This long starting pulse could be 10ms or more and it has two functions; it signals the starting of a new code and it prepares the IR receiver to detect properly the coming short pulses after it (without noise). Usually, the shortest interval is 1ms (if less the detection distance decreases).
Hope this helps.
Kerim