In the circuit given below, V(t) is the sinusoidal voltage source. Voltage drop VAB(t) across the resistance R

In positive half cycle, diode D2 is forward biased and diode D1 is reverse biased. In negative half cycle, diode D1 is forward biased and D2 is reverse biased and direction of current is opposite through R for positive and negative half cycles. Hence, output is not rectified.Since R1 and R2 are different, hence the peaks during positive half and negative half of the input signal will be different.