JP2877597B2 - Spectrum analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectrum analyzer for detecting a signal strength for each frequency band in audio equipment or the like.

[0002]

2. Description of the Related Art Conventionally, in various types of audio equipment, a signal strength display (spreader display) for each frequency band has been performed. For such display, a plurality of band-pass filters having different frequency bands are provided, and a signal for each frequency is obtained here. Then, the signal strength of the obtained signal for each frequency is detected, and the spectrum display is performed using the signal of the detection result.

Here, in a conventional device, all of these processes are performed as analog signal processes. However, with the advancement of computer technology and digital recording technology, signal processing in audio equipment has been performed entirely by digital processing using a DSP (digital signal processor) or the like. Therefore, there is a demand to perform the display of the spectrum by digital processing.

[0004]

In order to perform such frequency analysis in digital processing, a component of a predetermined frequency is extracted by a digital band-pass filter, and then a signal level is calculated for the extracted signal. It is considered good. For example, as shown in FIG. 3, the components of the frequency band to be displayed are extracted by the digital bandpass filter 10, and this is made only positive data by the absolute value unit 12. Next, the obtained data is integrated with the integrator 14.
Integrate until the solution settles according to the frequency at
This may be logarithmically converted by the logarithmic conversion unit 16 to be processed into data for display, and transferred to a microcomputer or the like that performs processing for display via the data transfer unit 18.

However, according to such a configuration, there is a possibility that the data to be transferred from the data transfer unit 18 may not be known as to which frequency. That is, as such a transfer method, it is conceivable that the transfer order is first determined in advance, and the data is sequentially transferred at a constant interval in that order. With this method, if a data transfer error occurs once, the subsequent data will be shifted,
There is a possibility that an erroneous spectrum analyzer display in which the signal level and the corresponding frequency band are different is performed. In particular, the microcomputer that receives data and performs processing for display also performs various display operations other than the display of the spectrum, and there is a sufficient risk that the received data will not be processed.

On the other hand, if measures are taken to prevent such data loss in the microcomputer for display, there is a problem that the number of steps of the program here increases and the load on the microcomputer increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a spectrum analyzer capable of efficiently displaying a spectrum.

[0008]

SUMMARY OF THE INVENTION A spectrum analyzer according to the present invention includes a plurality of bandpass filters for extracting signals of different frequency bands from a digital input signal, and a signal intensity of the extracted signals of the respective frequency bands. A plurality of power calculators each for calculating, a band information generator for generating band information for identifying which frequency band the signal belongs to, signal strength data output from the power calculator, and signal strength data synthesizing band information corresponding to the data synthesizing unit, have a data transfer unit for transferring the data from the data synthesizing unit, the signal strength
Combining data with corresponding band information
It is characterized by being transferred as one transfer data .

[0009]

As described above, in the present invention, the band information from the band information generator is added to
This is set as transfer data and transferred. For this reason, transfer data
On the display side receiving the data, it is possible to easily determine which frequency band of the power data, and the processing is facilitated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A spectrum analyzer according to an embodiment of the present invention will be described below with reference to the drawings. FIG.
Is a block diagram showing the overall configuration. The digital bandpass filter 10, the absolute value unit 12, the integration unit 14, the logarithmic conversion unit 16, and the data transfer unit 18 have basically the same configuration as the above-described example. ing. Note that the absolute value part 12, the integration part 1
4. The logarithmic converter 16 constitutes a power calculator.

In this embodiment, a band information generator 20 is provided corresponding to the logarithmic converter 16 of each frequency band to generate band information for identifying a signal of that frequency. Then, the band information from the band information generation unit and the data on the signal level from the logarithmic conversion unit 16 are synthesized in the synthesis unit 22 and supplied to the data transfer unit 18.

Here, in the present embodiment, the synthesizing section 22 is composed of a simple adder. Then, by adding the two data, as shown in FIG. 2, m-bit transfer data including band data for identifying data of which frequency and spectrum display data indicating a signal level is obtained. The data thus transferred is received by the microcomputer 24 and processed for display, and then the signal level for each frequency band is displayed on the display unit 26 as the length of the display lamp.

In order to perform such addition reliably, in the present embodiment, a pulse signal (for example, an A / D converter for converting an audio signal into an A / D signal) indicating the frequency of data input to the digital band-pass filter 10 is used. And a control unit 30 that generates an addition timing based on the count result.

As described above, the time until the integrated value in the integrator 14 corresponds to the signal level of the frequency band depends on the frequency of the signal. That is, the lower the frequency band, the longer the time until the signal level can be detected. Therefore, the control unit 30 detects a time corresponding to the frequency band, and sends a timing signal to the integrator 14 and the band information generator 20 at the detected time. Then, the integrator 14 receives this timing signal, outputs the integrated value at that time to the logarithmic converter 16, and combines the logarithmically converted data and the band information in the synthesizer 22.

Further, in this embodiment, up to the integrator 14, a 16-bit signal is handled and converted to 8 bits by logarithmic conversion, and this 8-bit data is output from the lower 8 bits of the 16-bit data bus. . Then, the data from the band information generator 20 is transferred to the upper 8
Data can be synthesized by inputting to the bits. In this case, the synthesizing unit 22 can be configured with an OR gate.

As described above, according to the present embodiment, since the band information is added, the microcomputer 24 receiving the data can perform display based on the band information. There is no problem even if a part of the data is discarded, and the processing in the microcomputer 24 is easy.

It is preferable that such a process for displaying a spectrum is performed by a DSP that performs a process of amplifying an audio signal (in particular, a process of changing an amplification factor for each frequency band). When processing is performed by such a DSP, it is difficult to obtain data of all frequency bands to be displayed for one sampling signal. Therefore, for example, when calculating signal levels of six frequency bands, 1
It is preferable to obtain signal levels of three bands from the sampled data, and obtain signal levels of the remaining three bands for the next sampled data.

In this case, the time required for the band-pass filtering and the calculation of the signal level is shorter for a higher frequency band. Here, assuming that the signals are a, b, c, d, e, and f from the low frequency band side, it is preferable to calculate them separately as a, c, e and b, d, and f. It is.
And, in this way, when the calculation order is changed,
It is particularly preferable to add band information as in the present invention.

[0019]

As described above, in the present invention, the band information from the band information generator 20 is added to the data to be transferred.
Therefore, on the display side receiving the power data,
It is possible to easily determine which frequency band the power data belongs to, and the processing becomes easier.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a spectrum analyzer according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of transfer data according to the embodiment;

FIG. 3 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 Reference Signs List 10 band pass filter 12 absolute value part 14 integration part 16 logarithmic conversion part 18 data transfer part 20 band information generation part 22 synthesis part 30 control part

Claims (1)

(57) [Claims] A plurality of band-pass filters for extracting signals of different frequency bands from a digital input signal; a plurality of power calculation units for calculating signal strengths of the extracted signals of the respective frequency bands; A band information generating unit for generating band information for identifying whether the signal is a band signal, a data intensity unit output from the power calculation unit, and a data synthesizing unit for synthesizing band information corresponding to the signal intensity data , possess a data transfer unit for transferring the data from the data synthesizing unit, a set and a band information and corresponding signal strength data
A spectrum analyzer characterized in that the data is transferred as one transfer data .