Doni , is this part of '' 774 '' patent claim that make the claim so unique that it
goes beyond recording only as opposed to removable memory use in many other devices?
From " 774 " patent
An additional significant feature of the present device comprises compression circuitry 41 and 42 coupled to the memory circuitry 24 (generally forming part of the control circuitry generally identified as 21) for compressing digital signal for storage in the flash memory module. This circuitry includes a DSP 41 and CODEC 42 which cooperate to compress data at a ratio of 16:1 for storage. Applying such data compression provides record times of 60 minutes or more, corresponding to traditional cassette tape recording times. These same components 41 and 42 cooperate as data retrieval circuitry for expanding compressed signal to a useful output signal to be sent to the speaker 36.
Those skilled in the art will be enabled to practice the present invention based upon the preceding functional description of the inventive features, referenced to the block diagrams of FIGS. 1 and 2. The following expanded explanation is provided to facilitate an understanding of the preferred embodiment of the invention as illustrated in the drawings for a handheld device for voice dictation and retrieval. Reference to block diagram numerals will be made where possible. More specific detail as to circuitry components will be understood by those skilled in the art and may be implemented with components currently available in the market.
Overall system design is based on the use of a microprocessor which can drive all system components. This eliminates the need for use of multiple interface logic that demands a lot of board space within the circuitry. The DSP or digital support processor is coupled to the microprocessor and to a CODEC for coding and decoding the analog signal received from the microphone or transmitted to the speaker. Codec also performs the analog to digital conversion. It functions to receive the analog signal input and convert it to PCM or pulse code modulation and then feed this signal to the DSP. Conversely, when operating in play back mode, the DSP will feed pulse code modulation digital signal to the codec and the codec converts it to an analog signal that can be fed through an amplifier to a speaker.
