JP3318386B2 - Field radio recording / reproducing device - Google Patents

Field radio recording / reproducing device

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Publication number
JP3318386B2
JP3318386B2 JP5281093A JP5281093A JP3318386B2 JP 3318386 B2 JP3318386 B2 JP 3318386B2 JP 5281093 A JP5281093 A JP 5281093A JP 5281093 A JP5281093 A JP 5281093A JP 3318386 B2 JP3318386 B2 JP 3318386B2
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Japan
Prior art keywords
frequency
recording
output
conversion
data
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JP5281093A
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Japanese (ja)
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JPH06265587A (en
Inventor
博之 見山
慶太郎 関根
Original Assignee
アルパイン株式会社
慶太郎 関根
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Publication of JPH06265587A publication Critical patent/JPH06265587A/en
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Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus, and more particularly to a field radio recording / reproducing apparatus capable of recording / reproducing while storing a frequency spectrum of a field radio.

[0002]

2. Description of the Related Art On-vehicle FM radio operated by the FM system,
In mobile phones, portable radios, etc., the desired signal is suppressed due to the presence of a strong input interference wave at a frequency adjacent to the desired wave frequency, multipath interference occurs in buildings and mountains, and distortion occurs due to overmodulation. For example, various reception failures unique to the FM system occur. For this reason, it is necessary to test and evaluate how much the in-vehicle FM radio and the like has resistance to these failures, and to improve the reception performance (field performance).
It is important to realize.

For example, to test and evaluate the interference immunity of an on-vehicle FM radio, a test radio is loaded on a vehicle,
Ideally, field tests would be performed at various locations, but this would take a significant amount of time. For this reason, conventionally, field radio wave conditions at various places are recorded by a recording device mounted on a vehicle, and field radio waves are reproduced in a laboratory based on the recorded data, and received by a radio under test to prevent interference. Test and evaluation.

FIG. 9 shows a configuration of a conventional field radio wave recording / reproducing system. At the time of recording, the received electric field intensity of each broadcasting station is measured by a plurality of electric field strength meters 3-1, 3-2,... Each electric field strength meter 3-1 and 3-
Are output to the personal computer 4 via the communication interface, and the field intensity data that changes in real time is recorded in the FD 5 for each broadcast frequency.

On the other hand, at the time of reproduction, the electric field intensity data recorded on the FD 5 is transmitted from the personal computer 6 to a plurality of standard signal generators 7-1 and 7- through the communication interface for each broadcast frequency.
Output to 2, ... Each standard signal generator 7-1, 7-
2,... Generate standard FM waves at different broadcast frequencies and change the amplitude (intensity) based on the electric field intensity data. The output of each of the standard signal generators 7-1, 7-2,... Is guided to the antenna 9 via the coupler 8, and a radio wave is radiated into the laboratory. As a result, a field radio wave whose electric field strength changes in real time is reproduced, so that the test and evaluation of the interference resistance of the target radio can be performed.

[0006]

However, in the conventional field radio wave recording / reproducing system, since only one parameter, the electric field strength of the field radio wave, is recorded / reproduced, the strong input interference resistance can be tested and evaluated. Interference resistance could not be tested and evaluated. This is because, for example, in the case of multipath interference caused by mutual interference between a direct wave and a reflected wave, a plurality of direct waves and one or a plurality of reflected waves having the same frequency and the respective electric field intensities and a phase difference varying in real time are provided. However, in the above-described field radio wave recording / reproducing system, 1
This is because, for one broadcast wave, only the combined electric field strength of the direct wave and the reflected wave can be recorded / reproduced.

In this regard, in the reproduction system of FIG. 9, the standard signal generators 7-1, 7-2,... Are controlled to have the same frequency, and the electric field strength and the phase difference change in real time. It is conceivable to generate a direct wave and one or a plurality of reflected waves to reproduce a multipath interference wave in a pseudo manner, but it is extremely difficult to analyze control parameters, and at present, it occurs in an actual field. Accurate reproduction of multipath interference is not possible. For this reason, the test and evaluation of the multipath interference immunity must be performed by repeating the field running,
It took a lot of time and effort.

Accordingly, an object of the present invention is to provide a recording / reproducing apparatus for a field radio wave capable of easily and quickly executing a test and evaluation of multipath interference resistance. It is another object of the present invention to provide a recording / reproducing apparatus for a field radio which can easily analyze a field radio at the time of multipath interference in a laboratory.

[0009]

According to the present invention, there is provided an antenna for receiving a field wave, an RF amplifying means for amplifying an antenna received signal, a local oscillator having a variable oscillation frequency, and a mixing circuit. A first frequency converter for converting the output of the RF amplifier circuit to a predetermined low frequency, a second frequency converter for converting the output of the first frequency converter to a lower frequency, a second a / D converting means for a / D conversion of the output of the frequency converter, fees
Field radio waves, some who received the multi-path interference in the field
Stomach, a field radio waves received adjacent-channel interference in the field,
Alternatively, A /
Digitally output the output data of the D conversion means to a predetermined recording medium
A digital recording means for recording, multipath interference resistance Ah
Testing , evaluation and modification of immunity to adjacent disturbances or overmodulation
Read and output data from the recording medium when performing
Digital reproducing means , a D / A converting means for D / A converting and outputting data output from the digital reproducing means, a local oscillator having a variable oscillating frequency and a mixing circuit, and an output of the D / A converting means. Frequency converting means for converting the frequency of the signal to a predetermined RF frequency, power amplifying means for power amplifying the output of the frequency converting means, and a multi-path connected to the output side of the power amplifying means to radiate radio waves to the surroundings and enter the laboratory. Obstruction
Harmful or adjacent jamming or overmodulated jamming
This is achieved by providing a reproducible antenna.

[0010]

According to the present invention, in a field, a radio wave is captured by an antenna, RF-amplified by an RF amplifier, and then converted to a predetermined low frequency by a frequency converter. And
A / D conversion is performed by A / D conversion means, and the digital recording / reproducing means records the data in a predetermined recording medium in a readable and writable manner.
Then, in a laboratory or the like, digital recording /
The data is read from the recording medium by the reproducing means, and the read data is D / A converted by the D / A converting means and output. This makes it possible to record / reproduce the waveform of the radio wave that changes in real time in the field, and if multipath interference occurs, recording / reproducing the combined waveform of the direct wave and the reflected wave.
Reproduction, that is, recording / reproduction of a multipath interference waveform can be performed. Once recording is performed in the field, the reproduction signal is directly or appropriately frequency-converted in a laboratory or the like, and then the reception system of the device under test is , It is possible to easily, quickly and repeatedly execute the test, evaluation, and improvement of the multipath interference immunity for the circuit subsequent to the injection point.

[0011] Further, according to the present invention, the predetermined frequency Feel
The de radio, recorded while changing the frequency, moreover, given
It is converted to an RF frequency signal and radiated from the antenna.
Therefore , multipath interference immunity , adjacent interference immunity ,
Testing, evaluation , and improvement of overmodulation resistance and the like can be performed .
In a laboratory or the like, after the frequency of the output of the D / A converter is converted to a predetermined RF frequency by the frequency converter,
The power is amplified by the power amplifying means, and radio waves are radiated from the antenna to the surroundings. This makes it possible to easily and repeatedly reproduce the field radio conditions at the time of multipath interference in a laboratory or the like,
The test, evaluation, and improvement of the multipath interference immunity of the entire device under test can be performed easily and quickly and repeatedly.

In the field, a radio wave is captured by an antenna, RF-amplified by RF amplifying means, and then converted to a predetermined low frequency by frequency converting means. And A / D
A / D conversion is performed by the conversion means, and the digital recording / reproduction means records the data in a predetermined recording medium in a readable and writable manner. As a result, once records are recorded in the field, it is possible to easily analyze multipath interference waves with a personal computer or the like on the reproduced data in a laboratory or the like, and develop equipment that is highly resistant to multipath interference. Can help.

In addition, a front end of a device to be tested for interference immunity is used for part or all of the RF amplification means and the frequency conversion means. This eliminates the need for preparing a special recording receiving system when recording in the field.

Further, after the data input from the A / D conversion means is compressed by the data compression means, the data is recorded on a recording medium,
The compressed data read from the recording medium is decompressed by data decompression means and output. This makes it possible to record the field wave waveform on the recording medium for a long time.

[0015]

FIG. 1 is an overall configuration diagram of a field radio wave recording / reproducing system according to a first embodiment of the present invention. Reference numeral 10 denotes an on-vehicle antenna, 11 denotes an on-vehicle FM radio as an example of a device to be tested for interference immunity, 12 denotes a front end,
3 is an IF circuit, and 14 is a detection / demodulation circuit. In the front end 12, 12a is the RF of the antenna reception signal.
RF amplifier for amplification, 12b oscillates at a variable frequency,
Local oscillator for outputting a local oscillation signal, 12c is a mixer mixing the RF signal and the local oscillation signal to frequency conversion into an intermediate frequency signal IF 1 of the center frequency f C1 = 10.7 MHz. I
In the F circuit 13, 13a is ± Δf around 10.7 MHz.
BPF, 13b is a first IF amplifier, 13c
And 13e are BPs that pass ± Δf around 10.7MHz
F and 13d are second IF amplifiers. First IF amplifier 1
3b is connected to the output terminal IF OUT, and B
The input side of the PF 13c is connected to the input terminal IF IN . In the detection / demodulation circuit 14, 14a is a limiter amplifier, 14b is an FM detector (DET), 14c is a noise canceller (NC), and 14d is a stereo demodulation circuit (M
PX).

Reference numeral 20 denotes an A / D converter for converting the waveform of the field radio wave to record / reproduce the data in the digital domain.
This is a recording / reproducing device that converts and outputs an A signal.
It has a F IN ′ and an output terminal IF OUT ′. During recording, connect the input terminal IF IN 'to the output terminal IF OUT .
The output terminal IF OUT ′ is connected to the input terminal IF IN . 21
Converting the local oscillator for outputting a local oscillation signal of a fixed frequency (= 10.25MHz), 22 is an intermediate frequency signal a second intermediate frequency signal IF 2 of the center frequency f C2 = 450 kHz the IF 1 is mixed with a local oscillation signal Mixer, 23 is cut-off frequency f C
LP for 700kHz band limiting and anti-aliasing
F and 24 are amplifiers that amplify the second intermediate frequency signal IF 'after passing through the LPF, and 25 is an amplifier that amplifies the second intermediate frequency signal IF'
A / D is converted at a sampling frequency of 1.8 MHz to output digital data to a buffer memory described later.
It is a D converter, and here it is assumed to be quantized to 8 bits.

Reference numeral 26 denotes a buffer memory which functions as an input buffer at the time of recording and as an output buffer at the time of reproduction. In this case, it is assumed that the buffer memory comprises 8 × 18 1-Mbit SRAMs and a write / read control circuit.
27 is a switch for performing system switching when writing to the buffer memory 26, 28 is a switch for performing system switching when reading from the buffer memory, and 29 is a switch for performing playback.
The digital data read from the buffer memory is
A D / A converter for performing A / A conversion, 30 an amplifier for amplifying the second intermediate frequency signal IF 2 ′ obtained by the D / A conversion, 31 an LPF for anti-aliasing, and 32 a second LPF after passing through the LPF. This is a mixer that mixes the intermediate frequency signal IF 2 ′ with the local oscillation signal input from the local oscillator 21 and converts it into an intermediate frequency signal IF ′ having a center frequency f C1 = 10.7 MHz.

Reference numeral 33 denotes a combination of the 8-bit data read from the buffer memory 26 into two 16-bit data at the time of recording, and further combining the combined 16-bit data with the Lch sample data and the Rch sample data alternately. The data is converted to digital audio interface format data while being
A first digital audio interface circuit 34 for outputting to a (digital audio tape recorder), at the time of reproduction, performs inverse conversion by dividing the digital audio interface format data input from the DAT into channels and further dividing the data into original 8-bit data. , A second digital audio interface circuit for outputting to the buffer memory.

Reference numeral 35 denotes a DAT. The output side of the first digital audio interface circuit is connected to the digital input terminal D IN, and the input side of the second digital audio interface circuit is the digital output terminal D IN.
Connected to OUT . DAT35 is DAT tape 3
6 in the recording medium, (during recording) recording time, removed Lch sample data and Rch sample data from the digital audio interface format data inputted to the digital input terminal D IN, interleaving,
Digital recording is performed by adding an error correction code and the like. At the time of reproduction, data recorded on the DAT tape 36 is read,
Performs processing such as deinterleaving and error correction.
The data is converted into digital audio interface format data and output from the digital output terminal DOUT .

FIG. 2 is a diagram showing the operation of the recording system, and FIG.
Diagrams showing the spectrum of the output of the / D converter, FIGS.
Are waveform diagrams showing the recording / reproducing performance of the recording / reproducing apparatus. Hereinafter, the operation of the present embodiment will be described with reference to these figures. The recording vehicle is equipped with an on-vehicle FM radio 11 to be tested and a recording / reproducing device 20, and is equipped with an on-vehicle antenna 10 and a front end 12.
And the output terminal IF OUT of the IF circuit 13 is connected to the input terminal IF IN ′ of the recording / reproducing apparatus 20. Then, the on-vehicle FM radio 11 is tuned to a certain broadcast frequency F IN . Perform a field run in this state,
The switch 27 is switched to the A / D converter 25 at a desired measurement location, and the writing operation is performed on the buffer memory 26.

After the reception wave of the frequency F IN is caught by the on-vehicle antenna 10, RF amplification and frequency conversion are performed by the front end 12 of the on-vehicle FM radio 11, and the BPF 13
By passing through the a and the 1IF amplifier 13b, the center frequency f C1 from the output terminal IF OUT intermediate frequency signal IF 1 of the band of the f c1 ± Delta] f is output at 10.7 MHz. Intermediate-frequency signal IF 1 is the center frequency is the same waveform as the reception wave of different, have the same spectral components as the receiving wave (FIG. 2
(See (1) and (2)).

The intermediate frequency signal IF 1 is supplied to the recording / reproducing device 20.
First, the center frequency f C2 is set to 450 kHz by the mixer 22.
In the converted second to an intermediate frequency signal IF 2 of the band of the f c2 ± Δf. Second intermediate frequency signal IF 2 also center frequency is the same waveform as the reception wave of different, have the same spectral components as the reception wave (see Fig. 2 (3)). Unnecessary components of the second intermediate frequency signal IF 2 are cut by the LPF 23 to prevent aliasing, amplified by the amplifier 24, and then A / D converter 25 converts the second intermediate frequency signal IF 8 into 8-bit data at a sampling frequency f S = 1.8 MHz. D conversion is performed.

[0023] spectrum of the A / D converted data, as shown in FIG. 3, the other original signal components centered at f C2, include aliasing components centered f S, 2f s, a .. However, the LPF 23 prevents the original signal component and the aliasing component from overlapping. A / D converter 2
8 is output from the buffer memory 2
By the operation of the write / read control circuit 6 (not shown), the data is sequentially stored in synchronization with the A / D conversion operation.
If the writing to the memory is repeated cyclically until the write stop command is received, for example, starting address → last address → starting address → last address → ..., multi-pass while monitoring the speaker output by ear When data relating to a desired field radio wave condition can be stored in memory such as when interference occurs or adjacent interference occurs, the write operation may be stopped. In the case of this embodiment, data for 10 seconds is stored in the buffer memory 26.

Next, after the switch 28 is switched to the first digital audio interface circuit 27 side, the digital recording of the DAT 35 is started and the reading operation of the buffer memory 26 is started.
By the operation of the write / read control circuit of the buffer memory 26, 8-bit data is sequentially read from the memory while being synchronized with the first digital audio interface circuit 33, and is output to the first digital audio interface circuit 33. The first digital audio interface circuit 33 combines the 8-bit data read from the buffer memory 26 into 16-bit data two by two, and further combines the combined 16-bit data alternately into Lch sample data and Rch data. while the sample data is converted to a digital audio interface format data to output to the digital input terminal D iN in DAT35.

The first digital audio interface circuit 33 first outputs the Lch sample data and R
For example, digital audio interface format data in which both ch sample data are FFFF 16 are output twice in succession, for example, so that cueing can be performed at the time of reproduction, and then data from the buffer memory 26 is format-converted and output. I do.

The DAT 35 extracts Lch sample data and Rch sample data from the digital audio interface format data input to the digital input terminal D IN , performs interleaving, addition of an error correction code and the like, and digitally records the data on a DAT tape 36. Go. When all the data is read from the buffer memory 26, the reading operation is stopped, and the recording of the DAT 35 is stopped. As described above, the received waveform that changes in real time at the frequency F IN is digitally recorded as it is by changing only the frequency of the spectrum, so that it is possible to reproduce even a received waveform in which multipath interference or adjacent interference has occurred. .
The same operation is repeated when a field radio wave is to be recorded in another radio wave condition such as another place.

[0027] When reproducing back to playing the laboratory, to connect the input terminal IF IN of IF circuit 13 recording / reproducing apparatus 20 and output terminal IF OUT 'of. Then, first, the switch 27 is switched to the second digital audio interface circuit 34 side. After rewinding the DAT tape 36 with the DAT 35 and reproducing the data, the data recorded on the DAT tape 36 is read, deinterleaving, error correction, and other processing are performed, and further converted to digital audio interface format data. Digital output terminal D
Output from OUT .

The digital audio interface format data output from the digital output terminal D OUT is input to the second digital audio interface circuit 34, and when two sample data of FFFF 16 are continuously input, a write command is input to the buffer memory 26.
After that, the digital audio interface format data is inversely converted and divided into the original 8-bit data and output. Upon receiving the write command, the write / read control circuit of the buffer memory 26 stores the 8-bit data sequentially in synchronization with the second digital audio interface circuit 34. Then, when the buffer memory 26 becomes full, the writing is completed.

Next, the switch 28 is switched to the D / A converter 29 to cause the buffer memory 26 to read data. Then, the write / read control circuit of the buffer memory 26 reads out 8-bit data sequentially from the memory at a rate of 1.8 MHz per second and outputs it to the D / A converter 29 while synchronizing with the D / A converter 29. . This reading is performed until a reading stop command is received.
It is performed cyclically in the order of the first address → the last address → the first address → the last address →.

The D / A converter 29 sequentially performs D / A conversion on the 8-bit data read from the buffer memory 26.
The output of the D / A converter 29 is amplified by the amplifier 30, then smoothed and anti-aliased by the LPF 31, and the second intermediate frequency signal IF 2 having the center frequency f C2 = 450 kHz.
'Is output. This second intermediate frequency signal IF 2
Is converted by the mixer 32 into an intermediate frequency signal IF 1 ′ having a center frequency f C1 = 10.7 MHz, and then output from the output terminal IF OUT ′ to the IF circuit 13 of the vehicle-mounted FM radio 11 to be tested.

In the on-vehicle FM radio 11, the intermediate frequency signal I
F 1 ′ is band-limited to 10.7 MHz ± Δf by the BPFs 13 c and 13 e and amplified by the second IF amplifier 13 d, and then input to the detection / demodulation circuit 14 and detected / demodulated. If an amplifier and a speaker are connected to the output side of the on-vehicle FM radio 11, a sound output when a field radio wave is received at a certain frequency can be confirmed by ear. If field radio waves are recorded at the time of various faults such as at the time of multipath interference, adjacent interference, overmodulation, etc., it is possible to test, evaluate and improve the interference resistance of the detection / demodulation circuit 14 and the like. .

Further, this test is not limited to the on-vehicle FM radio 11 used at the time of recording.
The intermediate frequency signal IF 1 ′ reproduced from the reproducing device 20 is represented by B
By injecting it into a predetermined location such as the input side of the PF 13c, it can be performed for each mass production set, and can also be performed for sets of different models. For example, if the second intermediate frequency is 450 kHz in a double heterodyne system set, the output of the LPF 31 can be injected into the second IF circuit. Further, the playback operation can be easily repeated any number of times simply by rewinding the DAT tape 36 of the DAT 35.

FIG. 4 shows a standard input signal (frequency 87.9 MHz, modulation signal 1 kHz monaural, frequency shift 75 kHz, input level
FIG. 5 is a diagram (frequency spectrum) showing the recording / reproducing performance of the recording / reproducing device 20 when 60 dBμ) is input to the antenna terminal of the on-vehicle FM radio 10, and FIG. 5 shows an input signal (87.9 MHz, Modulated signal 1kHz monaural,
FIG. 6 is a diagram showing recording / reproducing performance with respect to a frequency shift of 75 kHz, an input level of 60 dBμ, D / u 3 dB, and a phase difference of about 170 °. FIG. 6 shows an overmodulated input signal (87.9 MHz, modulated signal 1 kHz monaural, frequency shift 150 kHz, FIG. 3 is a diagram showing recording / reproducing performance with respect to an input level of 60 dBμ), and it can be seen that recording / reproducing is performed with good reproducibility.

According to the first embodiment, at the time of recording, in the field, the on-vehicle FM radio 1
1 is tuned to a certain broadcast frequency, the 10.7 MHz intermediate frequency signal taken out from the IF circuit 13 is taken into the recording / reproducing apparatus 20, and further frequency-converted to a second intermediate frequency signal of 450 kHz. The data is D-converted and digitally recorded on a DAT tape by a DAT 35 via a buffer and an interface. Then, at the time of reproduction, the DAT 35 is reproduced, data is read from the DAT tape, D / A converted through an interface and a buffer, and further frequency converted to return to an intermediate frequency signal of 10.7 MHz. Since the waveform of the radio wave that changes in real time in the field can be recorded / reproduced as it is, if multipath interference occurs, recording / reproduction of the combined waveform of the direct wave and the reflected wave,
That is, it is possible to record / reproduce the multipath interference waveform. Once recording is performed in the field, the reproduced signal is injected into a predetermined portion of the receiving system of the set to be tested in a laboratory or the like. The test, evaluation, and improvement of the multipath interference immunity with respect to the circuit subsequent to the point can be easily and quickly repeated over and over. The same is true when other interference such as adjacent interference or overmodulation interference occurs.

Further, the reception waveform in the RF band is changed to the second frequency of 450 kHz.
Since it was converted to an intermediate frequency signal and recorded, A /
The operating frequency of the D conversion and the D / A conversion can be reduced, and these conversions can be easily performed, and the data amount is reduced, so that the recording time can be extended. Furthermore, since digital recording / reproduction can be performed using DAT, the device configuration and handling are simple, and data preservability is good. In addition, since amplification in the RF band and conversion to an intermediate frequency signal can be performed using the front end of the test object set, there is no need to prepare a special recording receiver for recording in the field.

In the above embodiment, the test target set
The intermediate frequency signal extracted from the
Digital recording after converting to intermediate frequency signal
However, digital recording with the intermediate frequency signal
In this case, the local oscillation of the recording / reproducing apparatus 20 may be performed.
The circuit 21 and the mixers 22 and 32 become unnecessary. Conversely, the second
A third intermediate frequency signal IF having a lower frequency
ThreeMay be recorded after conversion.
In the raw system, the third intermediate frequency signal IF after D / A conversion Three´ → No.
2 IF signal IFTwo'→ like the intermediate frequency signal IF'
What is necessary is just to convert in reverse order. In addition, the number of IF
The BPF 13a in the road 13 is set as a through
13a records / reproduces intermediate frequency signals that are not band-limited
You may make it live. In this case, the band of the recording signal
Is determined by the LPF 23 of the recording / reproducing device 20.
You. Furthermore, the data reproduced by DAT35 is transferred to a personal computer,
Input to a spectrum analyzer, etc. to solve the waveform at the time of interference
Analysis, waveform processing and the like may be performed.

FIG. 7 is an overall configuration diagram showing a field radio wave recording apparatus according to a second embodiment of the present invention, which is mounted on a vehicle and records field radio waves. FIG. 8 is an overall configuration diagram showing a field radio wave reproducing apparatus according to the second embodiment, which reproduces a field radio wave in a laboratory or the like. First, referring to FIG. 7, 40 is an antenna,
41 is an RF amplifier for performing RF amplification of an antenna reception signal,
Reference numerals 42-1 to 42-m denote frequency converters, which sequentially convert the RF signals to lower frequencies. Frequency converter 4
2-1 comprises a mixer with a local oscillation circuit of the oscillation frequency is variable, the frequency of the received signal corresponding to the frequency of the local oscillation signal center frequency into a first intermediate frequency signal IF 1 constant at f C1 . The frequency converters 42-2 and below include a local oscillator circuit having a fixed oscillation frequency and a mixer.
2 The second of the first intermediate frequency signal IF 1 is a center frequency of f C2
Converted into an intermediate frequency signal IF 2, the frequency converter 42-3 to the condition that the center frequency of the second intermediate frequency signal IF 2 into a third intermediate frequency signal IF3 of f C3, low frequency by one stage And finally the frequency converter 42-m
Center frequency from outputs the m-th intermediate frequency signal IF m of f Cm.

The RF amplifier 41 and the frequency converters 42-1 to 42-1
The recording receiver 43 is constituted by 42-m. Here, the number m of stages of the frequency converter is an arbitrary number of 1 or more,
If m = 2, it becomes the same as the mixer 12c of the front end 12 and the mixer 22 of the recording / reproducing apparatus 20 in FIG.

[0039] 44 cut-off frequency f c performs the m-th intermediate frequency signal IF m center frequency f cm than is set as high Δf antialiasing etc. LPF, 45 is LPF
Outputting 2f c A / D converter for performing A / D conversion at a large predetermined sampling frequency than the 46 buffer memories for temporarily storing digital data according to a m intermediate frequency signal converted A / D, 47 A first digital audio interface circuit 48 for sequentially converting the data stored in the buffer memory into digital audio interface format data.
This is a DAT for taking out sample data of ch and Rch and recording it on a DAT tape 49.

The field radio wave recording device operates almost in the same manner as the recording operation of FIG. 1 except that the number of frequency conversions for the RF signal is set to m, and finally the m-th intermediate frequency signal output from the LPF 44. Since IF m has the same waveform as a received signal at a certain reception frequency at an antenna, although the frequency is different, the frequency spectrum of the received signal can be stored and digitally recorded.

Referring to FIG. 8, reference numeral 50 denotes a DAT which reads out Lch and Rch sample data recorded on the DAT tape 49 in a reproducing operation and outputs digital audio interface format data.
Is a second digital audio interface circuit for inverting the DAT output to extract digital data relating to the m-th intermediate frequency signal, 52 is a buffer memory for temporarily storing data output from the second digital audio interface circuit, Reference numeral 53 denotes a D / A converter which sequentially performs D / A conversion on the data stored in the buffer memory at the same predetermined sampling frequency as the A / D converter 45 and outputs an m-th intermediate frequency signal IF m '; L that is set to the same cutoff frequency as
PF.

Reference numerals 55-1 to 55-m denote frequency converters, which sequentially convert the m-th intermediate frequency signal IF m 'into higher frequencies. Frequency converter 55 -1~ 55 - (m-
1) comprises a mixer with a local oscillation circuit of the oscillation frequency is fixed, the frequency converter 55 -1 m-th intermediate frequency signal IF m '
Is the (m-1) th intermediate frequency signal IF whose center frequency is f Cm-1
was converted to m-1 ', the frequency converter 55 -2 (m-1) th
The center frequency of the intermediate frequency signal IF m-1 'is f Cm-2 (m
-2) The frequency is increased step by step by converting the signal into an intermediate frequency signal IF m-2 '. Frequency converter 5
5- m includes a local oscillation circuit and a mixer whose oscillation frequency is variable, and converts the first intermediate frequency signal IF 1 ′ input from the preceding stage into an R signal.
The signal is converted to a desired frequency in the F band and output. These frequency converter 55 -1 to 55 -m, respectively, performs the inverse frequency conversion and the frequency converter 42-m~42-1 in FIG.

Reference numeral 56 denotes a power amplifier for amplifying the output of the frequency converter 55- m, and 57 denotes an antenna connected to the output side of the power amplifier to radiate radio waves into a laboratory or the like.
The frequency converters 55 to 1 to 55-m and the power amplifier 56 constitute a reproducing transmitter 58.

This field radio wave reproducing apparatus operates in a completely opposite manner to the field radio wave recording apparatus shown in FIG. That is, the frequency converter 55- (m-1) except that the number of frequency conversions for the m-th intermediate frequency signal IF m 'is (m-1).
Up to the mixer 32 shown in FIG. 1 at the time of reproduction, and the frequency converter 55- (m-1) outputs the first
And outputs an intermediate frequency signal IF 1 '. The first intermediate frequency signal IF 1 ′ is converted into a desired frequency in the RF band by the frequency converter 55-m and output, and after the power amplifier 56 amplifies the power, the radio wave is radiated from the antenna 57 to the outside.

[0045] The radio wave, the frequency has the same frequency spectrum as the intermediate frequency signal IF m at the time of recording of different, previously, if a record of received waves received multipath interference field, the The multipath disturbance can be reproduced in the laboratory, and the test set prepared in the laboratory can be tuned to the radiated radio wave, so that the multipath disturbance in the front end, IF circuit, detection / demodulation circuit, etc. of the test set Testing, evaluation and improvement of resistance can be repeated easily and quickly. Similarly, if a received wave or an overmodulated received wave that has undergone adjacent interference in the field is recorded in advance, the interference resistance can be similarly tested, evaluated, and improved.

In the above-described second embodiment, the local oscillation frequency of the frequency converter 42-1 at the first stage of the field radio wave recording apparatus is made variable, but may be fixed. In this case, different frequencies can be received. By preparing a plurality of sets of the entire field radio wave recording device, it is possible to simultaneously record a plurality of transmission waves having different frequencies when recording in the field. In addition, the local oscillation frequency of the last-stage frequency converter of the playback device may be fixed, and if it is desired to radiate radio waves of different frequencies, a plurality of final-stage frequency converters having different local oscillation frequencies may be provided and switched. Good. If it is desired to radiate radio waves of different frequencies at the same time, a plurality of sets of the entire field radio wave reproducing apparatus having different local oscillation frequencies of the frequency converters at the final stage may be prepared. The buffer memory may be shared by the recording device and the reproducing device.

In both the first embodiment and the second embodiment, digital recording is performed without data compression.
The bit compression may be performed by the data compression circuit between the / D converter and the buffer memory or between the buffer memory and the first digital audio interface circuit. In this case, the bit compression may be performed between the second digital audio interface circuit and the buffer memory. Alternatively, bit expansion may be performed by a data expansion circuit between the buffer memory and the D / A converter. By doing so, the number of quantization steps of A / D conversion or D / A conversion is increased to perform conversion with higher accuracy, reduce the load on the capacity of the buffer memory, or increase the recording time. And so on. Furthermore, although FM broadcasting was taken as an example, RDS,
VICS and other data multiplex FM broadcasting, AM
The present invention can be applied to other types of transmission waves such as broadcasting and PCM broadcasting. For digital recording, instead of using DAT, another recording medium such as a semiconductor memory, FD, or HD may be used.

[0048]

As described above, according to the present invention, in a field, a radio wave is captured by an antenna, RF-amplified by an RF amplifier, and then converted to a predetermined lower frequency by a frequency converter. A / D conversion is performed by the A / D conversion means, and the data is readable and writable by a digital recording / reproduction means on a predetermined recording medium. Is read and the read data is output by the D / A conversion means by the D / A conversion means, so that the waveform itself of the radio wave which changes in real time in the field can be recorded / reproduced, so that multipath interference is obtained. , It is possible to record / reproduce the combined waveform of the direct wave and the reflected wave, that is, to record / reproduce the multipath interference waveform. After directly or appropriately converting the frequency of the reproduced signal, the signal is injected into a predetermined part of the receiving system of the device under test, so that the circuit downstream of the injection point can withstand multipath interference. Testing, evaluation, improvement can be easily and quickly many times repeatedly.

[0049] In addition, a field radio wave having a predetermined frequency, peripheral
Record while changing the wave number , and furthermore , to a predetermined RF frequency signal
Since it is converted and radiated from the antenna , the frequency
Multipath interference resistance , adjacent interference resistance , overmodulation resistance, etc.
Test, evaluate and improve . In a laboratory or the like, the output of the D / A conversion means is frequency-converted to a predetermined RF frequency by the frequency conversion means, then the power is amplified by the power amplification means, and radio waves are radiated from the antenna to the surroundings. In addition, it is possible to easily and repeatedly reproduce the field radio wave condition at the time of multipath interference in a laboratory or the like, and to easily, quickly and repeatedly execute the test, evaluation, and improvement of the multipath interference resistance of the entire device under test.

In the field, radio waves are captured by an antenna, RF-amplified by RF amplifying means, and then converted to a predetermined low frequency by frequency converting means. And A / D
A / D conversion is performed by the conversion means, and the digital recording / reproducing means is configured to record the data in a predetermined recording medium in a readable and writable manner.
In a laboratory or the like, multipath interference waves can be easily analyzed with a personal computer or the like on reproduced data, which can be useful for the development of equipment with high resistance to multipath interference.

Further, since a part or all of the RF amplification means and the frequency conversion means use the front end of the equipment to be tested for interference immunity, a special recording receiving system is used for recording in the field. No need to prepare.

Further, after the data input from the A / D conversion means is compressed by the data compression means, the data is recorded on a recording medium,
Since the compressed data read from the recording medium is decompressed and outputted by the data decompression means, the field radio wave waveform can be recorded on the recording medium for a long time.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating a field radio wave recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the recording operation of FIG. 1;

FIG. 3 is a diagram showing a spectrum of an output of the A / D converter of FIG. 1;

FIG. 4 is a diagram showing recording / reproducing performance with respect to a standard input signal.

FIG. 5 is a diagram showing recording / reproducing performance with respect to a multipath interference input signal.

FIG. 6 is a diagram showing recording / reproducing performance for an overmodulation interference input signal.

FIG. 7 is an overall configuration diagram showing a field radio wave recording device according to a second embodiment of the present invention.

FIG. 8 is an overall configuration diagram showing a field radio wave reproducing device according to a second embodiment of the present invention.

FIG. 9 is an overall configuration diagram showing a conventional field radio wave recording / reproducing system.

[Explanation of symbols]

11 On-vehicle FM radio 12c, 22, 32 Mixer 25, 45 A / D converter 26, 46, 52 Buffer memory 29, 53 D / A converter 33, 47 First digital audio interface circuit 34, 51 Second digital audio Interface circuit 35, 49, 50 DAT 36, 48 DAT tape

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-50-119529 (JP, A) JP-A-53-32607 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G01R 31/00 G01R 29/00 G01R 29/10

Claims (1)

(57) [Claims]
1. An antenna for receiving a field radio wave, an RF amplifying means for amplifying an antenna received signal, a local oscillator having a variable oscillation frequency and a mixing circuit, wherein the output of the RF amplification circuit is controlled to a predetermined low frequency. First frequency conversion means for converting the frequency of the first frequency conversion means, second frequency conversion means for converting the output of the first frequency conversion means to a lower frequency, and A / D conversion of the output of the second frequency conversion means / D conversion means and field radio wave which received multipath interference in the field
The or received adjacent interference Fields Field
And receiving radio waves to or overmodulation field wave,
The output data of the A / D conversion means in a predetermined recording medium.
A digital recording means for Ijitaru recording, multipath interference resistance or the adjacent interference resistance or excessive variations
When testing , evaluating , and improving the control tolerance,
Digital reproduction means for reading and outputting data, D / A conversion means for D / A converting and outputting data output from the digital reproduction means, a local oscillator having a variable oscillation frequency, and a mixing circuit. /
Radiates a frequency converting means for frequency converting an output of the A converting means into a predetermined RF frequency, and power amplification means for power-amplifying the output of the frequency converting means, the radio waves around and is connected to the output side of the power amplifying means
Multipath jammers or adjacent jammers in the laboratory
Or a device for recording / reproducing a field radio wave, wherein an antenna for reproducing an overmodulation interference radio wave is provided.
JP5281093A 1993-03-15 1993-03-15 Field radio recording / reproducing device Expired - Fee Related JP3318386B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5281093A JP3318386B2 (en) 1993-03-15 1993-03-15 Field radio recording / reproducing device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5281093A JP3318386B2 (en) 1993-03-15 1993-03-15 Field radio recording / reproducing device

Publications (2)

Publication Number Publication Date
JPH06265587A JPH06265587A (en) 1994-09-22
JP3318386B2 true JP3318386B2 (en) 2002-08-26

Family

ID=12925207

Family Applications (1)

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Country Status (1)

Country Link
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