Abstract:
A portable device is used for recording, editing, and replaying musical sounds generated by a musical instrument external to the device. The musical sounds are converted from analog to digital format, compressed for minimum storage usage, and stored in a digital storage medium. The stored signals are filed according to an indexing scheme that allows selection and retrieval of selected portions of the musical sounds. The selected portions are retrieved from storage, decompressed, converted back to analog signals, and output to a sound generating device. The operation of the device is controlled by application software and operating system software.

Description:
This application is a continuation of U.S. patent application Ser. No. 09/972,340 filed Oct. 5, 2001 now U.S. Pat. No. 6,605,769, entitled “Musical Instrument Digital Recording Device With Communications Interface”, which was a continuation-in-part of U.S. patent application Ser. No. 09/346,053 filed Jul. 7, 1999 abandoned, entitled “Musical Instrument Digital Recording Device With Communications Interface”, the disclosures of each of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to audio recording and playback devices. More particularly, this invention pertains to recording and playback devices for use in conjunction with musical instruments that are external to the device. 
     Musicians frequently have a need or desire to record the music that they create on their instruments. In some cases, the recording is made for personal enjoyment. In other circumstances, a recording will be made for more commercial purposes, such as to make a record of a song writing session to create a song demo recording, to create a musical instrument track for editing or mixing, or for archival purposes. Generally, musicians who want to record their music while playing an instrument will have to make special arrangements in a recording studio or use amateur tape recording equipment of their own. While in the recording studio, the musician has access to a variety of sophisticated post-production recording, mixing, and editing equipment. In a home recording setting, editing options are usually far more limited. In either case, the musician must plan the recording session in advance including gathering and connecting sophisticated, bulky recording equipment. During the recording session, the musician is often distracted from the actual playing of the instrument because he must use his hands to control the recording equipment and/or to change or reload the recording media. Even if a musician uses a portable cassette or mini-disc recorder for convenience, neither is specifically adapted for connection directly to an instrument such as a guitar. Moreover, existing portable recording devices have limited functionality and versatility in terms of editing and external connectivity. 
     U.S. Pat. No. 5,837,912, issued to Eagen, describes an apparatus for digitally recording music from a guitar. The apparatus also allows the user to replay the digitally recorded music. However, the Eagen device does not allow a user to edit the digitally recorded music or to access selected portions of the digitally recorded music. 
     Conventional portable recording and playback devices from Sharp Corporation and Diamond, such as the Sharp MD-MT821 and the RIO PMP300, provide the ability to digital record music from compact discs or from the Internet for time periods ranging from 1 hour to 8 hours. They do not provide the ability to edit the recorded music or record for longer periods of time. Moreover, these devices are not adapted for recording music directly from a guitar or other musical instrument. 
     Thus, there is a need for an audio recording and playback device that may be conveniently carried and operated by a musician to record the music he or she creates with a musical instrument. Preferably, such a device will have both internal storage that can easily be cued and reviewed as well as an interface to an external storage and editing device. 
     SUMMARY OF THE INVENTION 
     The musical instrument direct recording and playback device of the present invention comprises an input stage including an audio signal format converter having two analog inputs and outputs, an output stage including two digital outputs, a digital signal processor; a control input device: an application software storage device; an application software program, an operating system storage device; an operating system software program, a digital storage device; and a display. The device can connect directly to the output jack of an external musical instrument for purposes of receiving analog audio signals as the instrument is played. On commands entered by a footswitch connected to the device, the device converts the received signals to digital format, compresses the digital signals, and stores and indexes the digital audio signals on an internal mass storage device. On receipt of further commands, the device can retrieve selected portions of the digital signals, decompress the retrieved signals, converts the retrieved signals to analog signals, and output the analog signals as a monaural or stereo audio signal. The device includes an external communications port and interface, such as from a Universal Serial Bus, to a personal computer. This allows the stored digital audio data to be up-loaded for storage and editing and/or new or updated software to be downloaded. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic drawing of the musical instrument direct recording and playback device of this invention. 
         FIG. 2  is a plan view of a typical SHARC (Super Harvard ARChitecture) Digital Signal Processor device and circuit board that can be used in one embodiment of the device of the present invention. 
         FIG. 3  is a block diagram of the SHARC DSP device and circuit shown in FIG.  2 . 
         FIG. 4  is a flow chart showing the functional steps implemented by the software in one embodiment of the device of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , the present invention of a musical instrument recording and playback device  10  includes a recording input stage  12  and playback output stage  17  connected to a digital signal processor  14 , a control input device  16 , an application software storage device  18 , an application software program  19 , an operating system storage device  20 , an operating system software program  21 , a re-writable digital mass storage device  22 , and a display  24 . 
     The input stage  12  includes a first analog input  26  connected to a first digital input  42  on the processor  14  through a first analog data converter  27 , and a second analog input  28  connected to a second digital input  44  on processor  14  through a second analog data converter  29 . Optionally, first and second buffer amplifiers  37  and  39  can be used between the analog inputs  26  and  28  and corresponding analog data converters  27  and  29 . The converters  27  and  29  and be conventional A/D converters or CODEC devices capable of providing additional standard or proprietary format encoding on the input signals as they are converted to digital format at converter outputs  34  and  36 . 
     The analog inputs  26  and  28  are conventional female audio jacks adapted to connect directly to the output of a conventional external musical instrument  5 . The musical instrument  5  can be an electric guitar, keyboard, or other instrument that generates electrical analog and/or digital audio signals when the instrument is played by a musician. In a preferred embodiment, auxiliary audio output jacks  13  and  15  are hardwired directly to the analog inputs  26  and  28  so that an external connection can be made to other audio devices. In another embodiment of the invention, the device  10  can include digital signal inputs for direct connection to a musical instrument having a digital output. In this embodiment, the converters  27  and  29  would not need to perform an analog-to-digital conversion but would simply perform an encoding and/or decoding function to provide digital audio signals in the proper format. 
     The audio output stage  17  includes first and second digital outputs  64  and  66  on processor  14 , connected at converter inputs  30  and  32  to corresponding first and second digital data converters  41  and  43 . The outputs  38  and  40  of converters  41  and  43  can be buffered by buffer amplifiers  45  and  47  to provide analog audio output signals at first and second channel analog outputs  49  and  51 . Optionally, separate first and second auxiliary digital outputs  53  and  55  can be connected to processor outputs  64  and  66  for connection to external digital audio devices. The digital converters  41  and  43  are conventional type D/A converters or CODEC devices. 
     In a preferred embodiment of the device  10 , the converters  27 ,  29 ,  41 , and  43  can be integrated into a single CODEC integrated circuit and package. 
     The primary function of the input and output stages  12  and  17  is to convert analog signals generated by the musical instrument  5  to digital format during recording, and to convert the recorded digital audio signals back to analog format during playback. 
     The digital signal processor  14  includes a first digital input  42 , a second digital input  44 , a control input  46 , an application software storage input  48 , an application software storage output  50 , an operating system storage input  52 , an operating system storage output  54 , a display output  56 , a computer communications port  58 , a digital storage input  60 , a digital storage output  62 , a first digital output  64 , and a second digital output  66 . The processor  14  is of a conventional type found in the art such as the SHARC digital signal processor. 
     The primary function of the processor  14  is to compress the converted digital signals for storage purposes, store the compressed digital signals in files on the digital storage device  22 , control and manage the digital storage device  22 , receive inputs from the control input device  16 , retrieve stored digital signals from the digital storage device  22 , decompress retrieved digital signals, and send the decompressed digital signals to the converter  12  for conversion to analog signals. The processor  14  accomplishes all of the above tasks by using application software loaded on the application software storage device  18 . The application software is described in detail below. 
     The digital signals are compressed to ensure that the digital signals use up a minimum amount of space on the digital storage device  22 . In one embodiment of the device  10 , the digital storage device can be a conventional low profile IDE hard disk drive, and the processor  14  can communicate and control the digital storage device  22  through a conventional IDE disk controller interface. 
     The processor  14  compresses the digital signal received through the first digital signal input  42  and the digital signal received through the second digital signal input  44 . A compression algorithm is used to perform the compression. The compression algorithm is of the type commonly found in the art such as MPEG audio compression. 
     An external data port  48 , such as a USB port of the conventional type found in the art, is used to transfer stored audio data and programming from the device  10  to a remote computer (not shown). The digital audio data that is uploaded from the device  10  can then be stored, edited, mixed, etc. and, if desired, downloaded back to the device  10 . 
       FIGS. 2 and 3  illustrate one physical embodiment of the device  10  shown in block diagram form in  FIG. 1 , and particularly using a conventional SHARC DSP circuit board as the microprocessor  14  with onboard non-volatile memory (not-shown). A standard RS-232 serial communications port  48  is used to communicate with external devices in this embodiment, rather than a USB port. A UART (Universal Asynchronous Receiver Transmitter) and RS-232 Drivers convert the data as needed by the processor  14  and external device (not shown) in conventional fashion. 
     In accordance with one novel feature of the invention, the control input device  16  can be a momentary contact or multiple position footswitch that is capable of sending electrical signals or commands to the processor  14  by a wired or wireless connection to control input  46 . The control input device  16  generates control inputs to the processor  14  to control the operation of the device  10 . For example, when the control input device  16  is pressed one time, a control input is generated and sent to the processor  14 . The application software on the processor interprets this control input as a command to start and stop recording or to playback audio stored at a specific memory location. 
     Although the use of a footswitch that is hardwired to the device  10  is convenient for use by musicians who otherwise have their hands occupied, other conventional switches can be used, including switches operably connected to the device  10  by infrared or other conventional wireless means. Alternatively, a PC connected through a USB port can provide control commands to the device  10 . 
       FIG. 4  is a flowchart describing the sequence of commands and responsive operations that are implemented by the software controlling the microprocessor  14  in one embodiment of the present invention. As seen on  FIG. 4 , the device can operate in one of multiple modes based on the Select Mode, Select Record Mode, and/or Select Play Mode prompted by the processor  14  and entered by use of the control input device (footswitch)  16 . The primary modes include Select Record Mode, Select Play Mode, and File Dump Mode. 
     The record modes can include Record On Demand, Continuous Record, and Search. The Record On Demand mode requires further switch input by the user which, when received, initiates storage of audio signals along with generation of marker and indexing data. The Continuous Record mode activates recording, indexing, and marking whenever audio signals are present at a device input  26 ,  28 . The play modes include Index Play mode causes the device to begin playback of recorded signals located at specified index numbers. Additional detail is shown in FIG.  4  and described below. A programmer familiar with the programming language/instruction set associated with a particular microprocessor  14  would create and store the corresponding instructions and commands in the program storage device, such as the PROM  18 ,  19  on FIG.  3 . 
     The control input device  16  also controls the primary mode in which the device  14  is operating. When the control input device  16  is pressed five times in rapid succession, for example, the processor  14  enters a “Mode Setting Mode.” The display indicates this mode by displaying a “555” on the display  24 . 
     In a preferred embodiment, there are three recording modes for the musical instrument direct recording and playback device  10 . The first recording mode is the Continuous Record Mode that is selected when the user presses the control input device  16  six times. In the Continuous Record Mode, the device  10  records whenever an analog signal is present on analog inputs  26  and  28 . 
     The second preferred recording mode is the Record on Demand Mode that is selected when the user presses the control input device  16  seven times. In the Record on Demand Mode, the device  10  begins recording when the control input device  16  is pressed one time. The recording ends when the control input device  16  is pressed a second time. In one embodiment of the device, the processor is programmed to store audio data in six minute increments. If the control input device  16  is pressed when the device  10  is recording in the middle of a six minute recording increment, then a reduced mount of storage on storage device  22  will be used. For example, if a user records for three minutes and presses the control input device  16 , the device  10  will stop recording. When the user presses the control input device  16  to start a new recording, the device  10  will skip the remaining three minutes of the preceding six minute increment and start recording at the beginning of the next six minute increment. 
     A third recording mode is the Search Record Mode, selected when the user presses the control input device  16  eight times. In the Search Record Mode, the device  10  will not record over certain specified memory locations that the user has designated as protected. For example, the user may have several hours of recorded audio stored on storage device  22 . Within the second hour, and specifically, the first eighteen minutes of that hour, is recorded material that the user would like to keep stored at a specific memory location. The user designates this memory location as protected using the application software. 
     At some future time, the user may be recording over a memory location immediately preceding the memory location that the user would like to protect. When the device  10  reaches the protected material, the device  10  skips over the protected memory location and continues recording at the next available memory location. 
     In a preferred embodiment, there are four play modes for the device  10 . The Play Next Index Mode allows the user to replay the audio data stored at the next index number. This mode is selected when the user presses the control input device  16  one time. The Play Back Last Index Mode allows the user to replay the audio stored at the last index number. This mode is selected when the user presses the control input device  16  two times. The Play Back Last Marker allows the user to replay musical sounds stored at the last marker. This mode is selected when the user presses the control input device  16  three times. The Play Back Search Marker Mode allows the user to replay musical sounds stored at a given marker. This mode is selected when the user presses the control input device  16  four times. 
     An additional File Dump Mode can also be used. This mode is selected when the user presses the control input device  16  nine times. In the File Dump Mode, the device  10  transfers audio files stored on storage device  22  to a separate computer using external communications port  58 . The transferred data can include the corresponding index numbers and markers. 
     The application software storage device (ASSD)  18  is coupled to the processor  14 . The ASSD  18  contains the application software program  19  that responds to and causes processor  14  to execute user commands. 
     The operating system storage device (OSSD)  20  is electrically connected to the processor  14 . The OSSD contains the operating system software program  21  used to implement the compression of digital signals, store digital signals, retrieve stored digital signals, and transmit the retrieved digital signals to the output stage  17 . 
     Th operating system software  21 , application software  19 , and processor  14  cooperate such that the input stage  12  and output stage  17  can work concurrently, whereby new audio can be recorded and stored during the playback mode. 
     The digital storage device (DSD)  22  is electrically connected to the processor  14 . The DSD  22  is of the type commonly found in the art such as an optical or magnetic disk drive. It should be noted that many other mass storage devices could be substituted for the hard disk drive. Examples of substitutes include non-volatile FLASH memory cards, etc. In one embodiment of the invention, the processor  14  is programmed to overwrite the first recorded digital audio data stored on the DSD  22  when the DSD  22  is full. Flash Memory is used for easy and fast information storage in such devices as digital cameras and home video game consoles. It is used more as a hard drive than as RAM. In fact, Flash Memory is considered a solid-state storage device. Known examples of Flash Memory include a PC&#39;s BIOS chip, CompactFlash (most often found in digital cameras), SmartMedia (most often found in digital cameras), Memory Stick (most often found in digital cameras), PCMCIA Type I and Type II memory cards (used as solid-state disks in laptops), and memory cards for video game consoles. 
     More particularly, Flash Memory is a type of EEPROM chip. It has a grid of columns and rows with a cell that has two transistors at each intersection. The two transistors are separated from each other by a thin oxide layer. One of the transistors is known as a floating gate and the other one is the control gate. The floating gate&#39;s only link to the row, or wordline, is through the control gate. As long as this link is in place, the cell has a value of “1”. To change the value to a “0” requires a curious process called Fowler-Nordheim tunneling. Tunneling is used to alter the placement of electrons in the floating gate. An electrical charge, usually 10-13 volts, is applied to the floating gate. The charge comes from the column, or bitline, enters the floating gate and drains to a ground. This charge causes the floating gate transistor to act like an electron gun. The excited electrons are pushed through and trapped on other side of the thin oxide layer, giving it a negative charge. These negatively charged electrons act as a barrier between the control gate and the floating gate. A special device called a cell sensor monitors the level of the charge passing through the floating gate. If the flow through the gate is greater than fifty percent of the charge, it has a value of “1”. When the charge passing through drops below the fifty percent threshold, the value changes to “0”. A blank EPROM has all of the gates fully open, giving each cell a value of “1”. 
     The electrons in the cells of a Flash Memory chip can be returned to normal (“1”) by the application of an electric field, a higher voltage charge. Flash Memory uses in-circuit wiring to apply the electric field to the entire chip, or to predetermined sections known as blocks. This erases the targeted area of the chip, which can then be rewritten. Flash Memory works much faster than traditional EEPROMs because instead of erasing one byte at a time, it erases a block or the entire chip, and then rewrites it. 
     The CompactFlash and SmartMedia types of removable storage, as well as PCMCIA Type I and Type II memory cards, adhere to standards developed by the Personal Computer Memory Card International Association (PCMCIA). Because of these standards, it is easy to use CompactFlash and SmartMedia products in a variety of devices. Standard adapters are available that allow the microprocessor  14  to access these cards through a standard floppy drive, USB port or PCMCIA card slot. SmartMedia cards erase, write and read memory in write and read memory in small blocks (256 or 512 byte increments). 
     In an embodiment of the device  10  where an external FLASH memory device is used for DSD  22 , the digital storage input  60  and output  62  can be in the form of a second USB connector with an adaptor to connect to a SmartMedia or CompactFlash card, or a standard PCMCIA card connector with a PCMCIA FLASH memory device, all of which are conventional devices well known in the art. The microprocessor  14  reads and writes data to the FLASH memory type DSD  22  using the standards developed by the Personal Computer Memory Card International Association (PCMCIA). 
     The DSD  22  stores each digital audio signal as an individual file in six minute increments. It should be noted that the choice of six minute increments is arbitrary and may vary depending on the needs of the user. In addition, the DSD  22  may also combine each individual digital signal and store both digital signals as one stereo file. Preferably, the DSD  22  can hold up to 20 hours of musical sounds. 
     In accordance with a preferred embodiment, each six minute data increment results in the generation of an index number corresponding to that increment. For example, a six minute recording would have a 00 for an index number. A twelve minute recording would have two index numbers: 00 and 01. The index number 00 would represent the first six minutes of the recording and the index number 01 would represent the second 6 minutes of the recording. 
     The user of the device  10  can also insert electronic marker numbers at his or her discretion, using the input device (footswitch)  16 . These markers would be time stamped and would be numbered beginning with the number 1. The user of the device  10  can issue a command (also using input device  16 ) to move directly to each marker. The application software program  19  controls this function of the device  10 . 
     File names are created by using the date of the recording in month, day, and year format and the index number of the file. For example, a twelve minute recording created on Jan. 1, 1999 would result in two files having the file names 010199.000 and 010199.001. 
     A display  24  is electrically connected to a display output  56  on processor  14 . The display  24  can be a three or four digit LED display typically found in the art. The display  24  displays the index number for the current file that is being recorded or being played. For example, when the recording and playback device  10  has been recording for 26 minutes (and thus the current index number is 04) the number 04 is displayed on the display  24 . Likewise, when the recording and playback device  10  has been playing back a recording for two minutes, the number displayed on the display  24  is 00. Thus, the display can be used by the musician to locate and playback a specific portion of the recorded audio, using the displayed index numbers and/or markers. The display can also be used to provide visual command prompts to the user when a primary, record, or playback mode needs to be selected. 
     Thus, although there have been described particular embodiments of the present invention of a new and Musical Instrument Digital Recording Device with Communications Interface, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.