摘要:
There are provided a musical tone-generating apparatus which neither requires hardware having an increased circuit size nor imposes a heavy burden on a CPU thereof, and a mobile terminal apparatus including the musical tone-generating apparatus, as well as a musical tone-generating method, and a storage medium storing a program for executing the method. A CPU converts music contents data stored in a RAM to hardware tone generator control data, stores the resulting data into the RAM. In reproduction, the CPU reads out and sends the hardware tone generator control data to a hardware tone generator. A data decoder circuit of the hardware tone generator sequentially reads out the hardware tone generator control data from a FIFO and separates the read data into time management information and data of a parameter for generation of a musical tone, and sets the time management information to a counter. Under the control of the counter performing the time management, a register write controller writes data of the parameter into a tone generator control register at timing indicated by the time management information. A tone generator section produces the musical tone based on the data stored in the tone generator control register.
摘要:
An asynchronous signal input apparatus includes a memory device which writes data that are input at a predetermined frequency, in response to a write signal, and reads data in response to a read signal. A data quantity measuring device measures a data quantity representing a quantity of data stored in the memory device. A read signal generating device generates the read signal at a frequency that varies depending upon the measured data quantity. A sampling frequency conversion apparatus comprises the memory device, data quantity measuring device, and read signal generating device employed in the asynchronous signal input apparatus. Further, the read signal generating device includes a converter which performs non-linear conversion on the data quantity measured by the data quantity measuring device. An interpolation information producing device produces interpolation information to be used for data generated from the memory device, based on the data quantity to which the non-linear gain is given by the converter. An interpolation device interpolates data that are read from the memory device in response to the read signal, based on the produced interpolation information.
摘要:
An audio signal processor is composed of a data path unit, a mode register and a state machine unit. The data path unit applies one or more arithmetical operation to an audio signal for performing signal processing of the audio signal. The mode register stores mode information specifying the signal processing to be performed by the data path unit. The state machine unit sequentially feeds control signals according to the mode information for enabling the data path unit to apply one or more arithmetical operation to the audio signal so as to perform the signal processing. The performed signal processing is composed of the one or more arithmetical operations, and is specified by the mode information stored in the mode register.
摘要:
A digital signal processor is adapted to a working RAM, which is capable of storing a plurality of data in a rewritable manner and whose storage area is divided into a plurality of sub-areas that are designated by addresses in read/write operations, wherein an operation circuit performs calculations on the data of the working RAM in accordance with a program, and wherein upon detection of a non-access event in which the program does not need to access the working RAM, a write circuit compulsorily writes ‘0’ into the working RAM with regard to each of the prescribed addresses of the prescribed sub-areas subjected to initialization, which are designated by address data. Thus, it is possible to actualize the selective initialization on the prescribed sub-areas within the working RAM without increasing the scale of the peripheral circuitry, without requiring complicated controls, and without increasing the overall processing time therefor.
摘要:
A digital signal processor and digital signal processing method are provided, which are capable of performing plural kinds of signal processing, and also performing processing for storing sampled data in a manner corresponding to respective kinds of signal processing with a small amount of hardware even in the case where the manner of storing and reading sampled data to be processed with respect to a memory device is different between the plural kinds of signal processing. A storage device stores plural kinds of sampled data corresponding, respectively, to plural kinds of signal processing. A counter updates a count value thereof every sampling period and generates the updated count value as a basic address. A sampled data input and output device performs an input and output operation every sampling period, the input and output operation comprising generating plural kinds of offset addresses corresponding, respectively, to the plural kinds of signal processing and not overlapping with each other, generating at least one write address or read address for the sampled data for each of the plural kinds of signal processing by modifying the basic address by at least one of the offset addresses corresponding to each of the plural kinds of signal processing, and delivering the generated at least one write address or read address to the storage device.
摘要:
Periodically sampled digital data (e.g., digital audio data) are once stored in a work RAM and are then subjected to signal processing such as arithmetic operations using coefficients. A primary accumulator register stores results of arithmetic operations. A secondary accumulator register is specialized in handling a relatively high processing load (e.g., down-sampling) having a plurality of steps, which are distributed and appropriately assigned to a plurality of periods in response to output timings. In order to execute other processing in each period, intermediate results of arithmetic operations regarding the relatively high processing load are temporarily stored in the secondary accumulator register. The number of steps assigned to each period is appropriately changed in response to interruption of the other processing, whereas the relatively high processing load is given a first priority in comparison with the other processing.
摘要:
Register includes flip-flop circuits each constructed to retain data of n bit in synchronism with a clock pulse, the register retaining a multiplication result of a multiplier dividedly by the flip-flop circuits, n bit per flip-flop circuit. For each of a first and second numeric value data to be multiplied by the multiplier, a control circuit detects the number of consecutive zeros from the lowest-order bit of the data and performs control, on the basis of the detected number of the consecutive zeros and for each flip-flop circuit, as to whether or not the clock pulse should be supplied to the flip-flop circuit. The control circuit obtains an integral quotient value x by dividing by the number n the sum between the detected numbers for the first and second numeric value data, to stop the clock pulse supply to a particular number x of flip-flop circuit counted from the lowest-order.
摘要:
There is provided a musical tone reproducing apparatus, which stores tone color parameters in a general-purpose storage means, to thereby shorten the time taken for a tone color changing process. A CPU 10 registers a tone color parameter group that has been read out from a RAM 11 in a tone generator memory 30, which is a general-purpose memory, in advance. The tone color parameters required when a tone generation core 33 carries out musical tone reproduction are stored in a cache memory 32 for all channels. Upon the CPU 10 giving a tone color changing command to a controller 31, a specified tone color parameter is read out from the tone generator memory 30. The tone color parameter for a specified channel in the cache memory 32 is then rewritten with the read out tone color parameter. The tone generation core 33 reads out from the cache memory 32 the rewritten tone color parameter set for each channel, and hence musical tone reproduction with a changed tone color is carried out. Because a tone color parameter group of a freely chosen number of tone color parameters has been registered in the tone generator memory 30, the need to transfer a tone color parameter from the CPU 10 to the tone generator memory 30 each time a tone color is to be changed can be removed as much as possible. Moreover, the output bit width of the cache memory 32 is made to be large, and hence the tone color parameter the tone color parameter can be set into the tone generator means instantaneously. Consequently, even though the tone color parameters are stored in advance in the general-purpose storage means, the time taken for the tone color changing process can be shortened, and hence the occurrence of a break in sound generation during tone color changing can be prevented.
摘要:
There is provided a musical tone reproducing apparatus which is capable of recovering proper timing of musical tone generation even in a situation where processing of events takes much time such that the sounding timing of musical tones is delayed. Duration data read out from a FIFO 30 are added together by a duration forward counter 32b. A comparator circuit 32d compares the count value of an absolute time counter 32c and the count value of the duration forward counter 32b, and delivers the comparison result i to a FIFO controller 3 when the former becomes equal to or more than the latter. The FIFO controller 31 causes the FIFO 30 to read out event information and delivers the same to a decoder 32a, which in turn converts the event information into tone generator control data having a format peculiar to a tone generator 33 and delivers the same data to a register write controller 32e. The register write controller 32e writes an associated tone generator parameter into a tone generator control register within the tone generator 33, and the tone generator 33 reproduces and outputs musical tones based on the tone generator parameter.
摘要:
A digital signal processor performs signal processing corresponding to a designated one of a plurality of sampling frequencies. A slot changing device carries out changeover of slots at a frequency equivalent to a common multiple of the plurality of sampling frequencies. A slot cycle setting device sets a slot cycle formed of the slots corresponding in number to a sampling period determined by the designated one of the plurality of sampling frequencies. An executing device executes routines corresponding to the slots forming the slot cycle, with a repetition period determined by the set slot cycle, to thereby perform signal processing corresponding to the designated one of the plurality of sampling frequencies in a time-discrete manner.