In this paper, we estimate the effect of joint Adaptive Multirate (AMR) compression and channel coding on quality of speech data. In our simulation, speech data is transferred over AWGN channel after performing 8 AMR codec modes (corresponding to 8 different compression rates) and 12 convolution code rates. The joint effect is estimated in the receiver by analysing quality of received speech data by Mean Opinion Score. Our result shows that conventional scheme performing source coding and channel coding seperately and sequentially does not guarantee obtaining the optimal solutions for speech data