for use in next generation mobile radio equipment 0028 fig1 shows a speech coder or vocoder system 100 that samples analog speech or some other signal from a microphone 105 an a to d converter 10 digitizes the sampled speech to produce a digital speech signal the digital speech is processed by a mbe speech encoder unit 115 to produce a digital bit stream 120 suitable for transmission or storage typically the speech encoder processes the digital speech signal in short frames where the frames may be further divided into one or more subframes each frame of digital speech samples produces a corresponding frame of bits in the bit stream output of the encoder if there is only one subframe in the frame then the frame and subframe typically are equivalent and refer to the same partitioning of the signal in one implementation the frame size is 20 ms in duration and consists of 160 samples at a 8 khz sampling rate performance may be increased in some applications by dividing each frame into two 10 ms subframes 0029 fig1 also depicts a received bit stream 125 entering a mbe speech decoder unit 130 that processes each frame of bits to produce a corresponding frame of synthesized speech samples a d to a converter unit 135 then converts the digital speech samples to an analog signal that can be passed to a speaker unit 140 for conversion into an acoustic signal suitable for human listening 0030 fig2 shows a mbe vocoder that includes an mbe encoder unit 200 that employs a parameter estimation unit 205 to.