Logic Levels, are by definition static, therefore have zero frequency. If a logic signal is time-varying between two logic states, then according to Fourier, you can analyze it to find its frequency components.
Unlikely that a periodic or aperiodic logic waveform would have only two frequency components; more like an infinite series of them...
I know nothing about Proteus. However, finding the frequency components of any arbitrary waveform, be it a logic waveform or something else, requires doing a Spectral Analysis or Fourier Analysis.
i have two pulses each having different pulse duration and wanted to ask whether they have different frequency and if so how i can get the frequency values.
If you have a burst of pulses, or a continuing train of pulses, you could say that the "Pulse Repetition Frequency" (PRF) is (say) 1000 Pulses Per Second (PPS), which would be the same as 1000Hz.
Are these two pulses which are of different duration on the same line?
If there is just two pulses, there is really not much you can say about frequency.
If they just have different pulse duration, then that is pulse width modulation (PWM). While PWM is often used for controlling power, it is also a useful method for some types of (e.g., servo) control. To determine the frequency, you need to measure the time for a whole period. That is, from the beginning of the first high (or low) to the beginning of the next high (or low).
both pulses are on the same line and are alternating one after the other so we cannot say anything about the frequency from the context of pulse repetition, is this so?
To have those pulses occurring "one after th other" and never at the same time, they should be ocurring at the same rate. Otherwise, sooner or later one would step on the other.
You are also talking of duration...
You should tell the complete story of your homework.