JPS6089861A - Rotary head type recording and reproducing device - Google Patents

Abstract

PURPOSE:To allow the titled device to cope with plural sampling frequencies by changing the number of revolutions of a drum and a tape feeding speed in response to the ratio of frequencies in switching the sampling frequency. CONSTITUTION:A sampling frequency switching circuit 31 is activated by the sampling frequency. A clock frequency division circuit 30 changes the clock frequency by using an output of the circuit 31. Then a servo circuit 19 controls a rotary drum 8 and a capstan 11 in synchronizing with the clock frequency subject to change. Thus, the device copes with plural sampling frequencies.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a rotary head'm and a PCM recording/reproducing device, and in particular, the present invention relates to a rotary head'm and a PCM recording/reproducing device, and in particular, it is possible to convert signals quantized at different sampling frequencies to the same recording linear density and the same tape pattern. The present invention relates to a PCM recording and reproducing device that records and reproduces data in a PCM format.

[Prior art]

General lfJ of PCM recording and reproducing device using rotating head
The structure is shown in Figure 1. In the figure, (1) is an analog signal input terminal (#), (2) is a low-pass filter for cutting all high frequency components of the analog input signal on the recording side,
(3) is a circuit for converting the analog signal tsump μH) V l' into a digital /l/signal, (4) is the buffer memory on the marking hand side, and (5) is the memory circuit (
4) An encoding circuit for generating and adding all 91 positive codes to the stored data, (6) a circuit for modulating the '1q° encoded signal, and (7) recording and reproducing. The switch for changing the operation, (8) is the 11th mudotsum, (
9) is a recording/reproducing head provided on the drum of (8);
al is the magnetic tape, [111 is the tape α (defined as
! The capstan for the transmission, θ2, is fixed with a nail, and the circuit for adjusting the transmission, θ old circuit θ2.
It is demodulated by 1. : A buffer memory circuit on the playback side for sequentially storing signals; θ→ is a decoding circuit s for decoding data stored in (181) and correcting errors;
``l'' is a digital/analog conversion circuit for returning this data to the original analog signal, and ``l'' is a reproduction side low-pass filter ``L'' (171 is Analog signal output: 1 output terminal, at is a circuit that generates a master clock for each block (7'llll), (11n is (8)
This is a servo circuit for full control of the drum and (111) cab's tongue.

In such a PCM and ID recording device, the frequency at which the analog source signal is sampled in the sample 7 rehold circuit (3) is the sampling frequency F8.
For example, 48KH2 and 44. IKHz mat
32I (H2 etc.) is selected.

Now, an example of the code and tape pattern format when Fa=48I (Hz) will be explained below.Fs=
In 48KH2, the number of samples/L/number of digital signals generated per second is 96,000 words in stereo. If reading and writing onto the tape are performed by two heads (9) installed on the drum (8), and the rotation speed of the drum (8) is 180 Orpm, or 30 Hz, the number of tracks on the tape is Since there are 960 samples per second, the number of samples that can be put into one track is 1600 words.

This 1600-word data is stored in the memory circuit (5) and encoded. Here, for example, if we chop it into 8-word data and add all the error control codes of P and Q2 words, the structure of one frame is as follows. It will look like Figure 2. l frame contains 8 words of data, so 200
One track's worth of data is completed in a frame. This is shown in FIG. In Fig. 3, F(lsFl indicates each frame!
When considering the application of the device 'j to a digital 7 radio, the interval 151 is the sampling frequency. That is, even today, as a digital PTV audio stimulus, l? 5=32KIIz, 44. II (Hz48K
Several sampling frequencies, such as Hz, are used, and a device that can accommodate these multiple sampling frequencies is desired. However, in the conventional method, in order to cope with multiple samplings, the sampling frequency 'L
The choice is to use all the converters or to interface in the form of analog signals. The I'+j1 type is very uncommon, with 1° and 1111 degrees, and the latter has the drawback of being accompanied by a deterioration in quality.

[4 Summary of the Invention] This invention eliminates the drawbacks of the conventional ones as described above.
The purpose of the present invention is to provide a rotary head type recording and reproducing device capable of handling multiple sampling frequencies by changing the drum rotational speed and tape feeding speed in proportion to the sampling frequency. It is said that

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The entire drawings of an embodiment of the present invention will be described below. Fourth
An example is shown in the figure. The figure shows the sampling frequency F
The sampling frequency switching circuit 1) operates in accordance with s, and the clock frequency at is changed by the clock frequency dividing circuit 09). 7t
il+'! ! - This is a controlled example.

FIG. 5 is a block diagram showing the clock frequency dividing circuit of FIG. 4 in more detail. Here, the sampling frequencies are 48KHK and 52KHz.The master clock is 48KHz and 32KHz.
'j-small common multiple i. 48KHz x 6 = 288
I(Hz)

(In actual systems, a much more flexible frequency is often chosen.) This master clock generation is performed at q. 1) is a variable divider, and by specifying the sampling frequency, 1/6 or 1/9 frequency division is selected. Specifically, a preset counter or the like is used. "This": The sampling frequency is 48KJIz
- or 32K [l z is i1). Sampling frequency cutting 49! For example, the frequency divider (211) is used to specify the numerical value of the preset counter, which is shown in (3). The frequency divider 1) is for the sampling frequency tl/8e, and the drum motor rotation layer J, !II is set to 60112- or 40IIZ depending on the sampling frequency. On the other hand, the frequency divider η is 1
/400 (12Hz or (18H) depending on the total sampling frequency of the capstan motor selected for IQ
It can be Z.

Here, the capstan is 1 white, diameter k 1.59 inch.
Since the speed is ++16, the tape feeding speed is 5 mm/S at 12 Hz. Therefore, the tape feeding speed is not a fixed value depending on the diameter of the capstan. In addition, the drum rotation speed of 1800 rpm, for example 1
Values such as /40000 frequency division are values that can be changed depending on the system design and are not fixed values.

Now, it will be explained below that the above 114 configuration can support a plurality of J-combining frequencies. Please refer to Figure 6.

Sampling frequency: Fs (Hg) Quantization bit *: Qb (bit) shall be.

Audio channel fiber: Ch Redundancy: C8 If the data bit rate is tK, then K = QbXChXCIX Fs (BPS) (1
)Rotating drum N (rpm), number of heads H (pieces), information amount per track I, tape speed VT,) rack pitch tpsF hook angle θ
Then, VT""'-ASINθX It) (3) 60 □ If the track length is t5 and the linear recording density is 1d, then t=I/Id
(4) Let the relative speed of the tape and head be vvH, and the drum diameter be φ. Above, in (1) to (8), the following assumption is 11t<
.

0 number of audio channels Ckl: '0 redundancy level C
1'' 0 Held M)l:'O Recording Density 1d:'01) Rack ゛Report: I&l:.

Let us consider a case where the sampling frequency Fsi is changed under the above conditions.

■ According to formula 1, the data bit rate must be proportional to Fs ■ According to formula 3, the tape speed VT is proportional to the drum rotation speed Q ■ According to formula 4, the track length t takes a constant value ■ According to the 5th type, the relative speed VH is proportional to the drum rotation speed N. ■ According to the 6th type, the drum circumferential speed Vd is proportional to the drum rotation speed.

(2) <7) From equation (8), the track inclination angle θ takes a constant value, and the head trajectory does not change even if Fse is changed.

In summary, when recording and reproducing signals quantized at multiple sampling frequencies with the same recording linear density and the same tape pattern format, Q: change the drum rotation speed in proportion to the sampling frequency (2) The tape feeding speed is changed in proportion to the sampling frequency. The data bit rate recorded and played back on the tape is proportional to the sampling frequency. By just changing the above three points, it is possible to obtain a device that is compatible with a plurality of sampling frequencies.

As an example, Fs=48KI(zzNt=1800rp
mjVTl= 61+11/ Sl 80G=120O
rpm, VTl = -x6 = 4/S, then 8.

In addition, in the above example, Fs=481UIz k 32K
I explained the case of switching to Hz, but 4411
(This can be achieved using a similar method at any sampling frequency, including the case of Ill.) Although it was explained that the drum rotation speed and tape feed speed are fully controlled by dividing the master clock frequency by gold, the preset values cannot be used. A switching speed reduction mechanism may be made of gold film.Alternatively, a synthesizer type clock generator may be used.

〔Effect of the invention〕

As described above, according to the present invention, in order to realize a device compatible with a plurality of sampling frequencies, a means for varying the drum rotation and tape feeding speeds proportional to the sampling frequency is provided, so the device can be made inexpensive and Since high accuracy can be obtained and the recording linear density can be kept the same, when the sampling frequency is lowered, the recording and reproducing time can be extended even with the same tape length.

[Brief explanation of the drawing]

Figure 1 is a Glock diagram showing the general configuration of a PCM recording and reproducing device using a rotating head, and Figure 2 is a sampling frequency F.
s=48K)Iz, drum rotation speed N=180Orpm. FIG. 3 is a signal configuration diagram showing the configuration of one frame in the case of two heads. FIG. 3 is a diagram showing the tape pattern when written on the tape in this way. FIG. The figure is a block diagram showing a clock frequency dividing circuit embodying the present invention, and FIG. 6 is a configuration diagram showing a tape format. (8) is the drum, (Ill is the capstan, 'Q81
is the master clock circuit, (++9 is the servo circuit, cue
is a clock frequency divider circuit, f2Lll (211 (2S2 is a frequency divider, respectively; MaO1θH1 No. 61゛4 +J#L Thea to the running chair・If you don't kill your throat at once: Chi 7
°Su Hayabusa, J.K., head and head included; ¥1, Commissioner's Palace 1, Indication of the incident, Patent Application No. 197808 2, Name of the invention, Rotating head type recording and reproducing device 3, Person making the amendment, Representative Katayama Section 5: Claims of the specification subject to amendment, detailed description of the invention, and brief description of drawings, and drawings. a Contents of the amendment (1) The entire text of the specification is to be corrected in the attached sheet. (2) Correct 2v in the attached sheets of Figures 1, 8, 4, 5, and 6 of the drawings. 7 List of attached documents (1) Amended specification 1 copy C2) Corrected drawings (Fig. 1, Fig. 8, Fig. 4/Fig. 5,
Figure 6) One or more copies of the original text 1 Title of the invention Rotating head type recording/reproducing device 2 Claims & Detailed description of the invention [Technical field of the invention] This invention relates to a rotating head type recording/reproducing device. Person in charge. In particular, the present invention relates to signals recorded at different sampling frequencies, recorded and reproduced using the same linear density and the same tape pattern format. [Prior Art] FIG. 1 shows a general configuration of an FC rotary head type recording/reproducing apparatus using the PCM transmission method. In the figure, (1) is the analog signal input terminal, and (2) is the high frequency component of the analog input signal on the recording side. Low-pass filter for cutting, (3) is analog FJ No. K Sunf. (4) is a buffer memory circuit for recording [111];
) is an encoding circuit for generating and adding a correction code to the data stored in the memory circuit (4), (61 is an encoded code a?!: a circuit for modulating it, ( 7) is a switch for switching between recording and playback operation, (81 is a rotating drum, (9) is a general playback head provided on the rotating drum (8), αO is a magnetic tape, and ill is a tape (
1 (12 Cabs Dan for constant speed feeding, 021 is the circuit % for demodulating the reproduced signal tone (131 is the circuit 0
21''' C demodulated n, 4 @ number sequential storage memory circuit on the playback side,
Decode the tLk data and correct the error? % (IIQ &;l' (% extra frequency Na(fil)
k *excluding tth regeneration 111110-bus filter, Ω
η is an analog signal output terminal, H&;1?11. A circuit for generating the tth master clock that controls block r, Q
9) is the rotating drum (8), capstan full k
This is a servo circuit for flill moaning. In the PCM recording internal generation device with such a configuration, the frequency at which the analog signal is sampled by the sample hold circuit 蒽31 is called the sampling frequency Fs. For example, 4 BK Elz or 441KHz
Or 82KHz etc. is selected 11. Ru. Now, what is an example of the code and tape pattern format when FS = 48K)12? 'asl under I-1
I will clarify. At Fs = 48 KHz, there is a sample of TE isotar No. 11 generated in one second. There is writing and reading on the tape. There are two heads (f') installed on the drum (8) at 180 degrees from each other. 9), and the rotation speed of the drum (8) is 180 Orpm.
In other words, if the frequency is 80 Hz, the number of tracks on the tape is 60 per second, so the number of samples that can be stored in one track is 1600 words. This 1600 word data is stored in the 2nd memory circuit (5) and encoded.
For example, assuming that P and Q2 words of error control codes are added to 8 words of data, the structure of an l frame will be as shown in FIG. 2. Since one frame contains eight words of data, one track's worth of data is completed in 200 frames. This is shown in FIG. In Figure 8, Fo, Fl... are the frame numbers? show. By the way, when considering the application of this PCM record playback device to digital audio, the problem is the sampling frequency. In other words, even now, as a digital audio support, Fs = 82KHz + 44, 1 to 1
(Several sampling frequencies such as 48KHz are used, and it is desirable to have a device that can handle multiple sampling frequencies.However, in the conventional method, it is difficult to handle multiple sampling frequencies.) Either a frequency converter was used, or the interface was made in the form of an analog signal.
There were 11 songs, which were not common, and the latter had the disadvantage of deteriorating quality. [Summary of the Invention] This invention was made in order to eliminate the drawbacks of the conventional products such as the one above. It is an object of the present invention to provide a rotary head type recording/reproducing device that can adapt to a plurality of sampling frequencies by adjusting the feed rate. I will explain about the 4th
An example of this in the figure? Boss. In the figure, according to the sampling frequency aFs → J° sampling frequency switching circuit C1
1), the clock frequency is changed by the clock frequency dividing circuit (7), and the rotating drum (8) is synchronized with the changed clock frequency by the servo circuit.
), which controls the capstan fill'. FIG. 5 is a block diagram showing the clock frequency dividing circuit of FIG. 4 in more detail. Here, the sampling frequencies of 48 KHz and 82 KHz will be explained. The master clock is generated at 43KH2x6=288KHz, which is a common multiple of U48KHz and 82KHz. (
(In actual systems, a frequency even higher than fL is often selected.) This master clock generation is performed at 0 barrels. The wire is a variable divider, and 1/6 or 1/9 frequency division can be selected by specifying the sampling frequency.
Ru. Specifically, a preset counter or the like is used. In this way the sampling frequency is 48KHz or 8KHz.
2KHz is obtained. Sampling frequency switching circuit Oη
For example, if 1 is the number of preset counters ILt? c- It is something that adds a finger. Next, a drum motor control signal is obtained by the branch unit &D, and a capstan control signal is obtained by the branch unit (a). Divider a! D is a frequency divided by the sampling frequency Q17160, and can be set to the drum motor frequency 2go)Iz or 20Uz depending on the summing frequency. On the other hand, frequency divider (2) ti
Rotation of the cab stan motor selected as t/4QOOQ, frequency t12Hz or Q8 depending on the sampling frequency
Hz. Here, the capstan diameter Q
Since the tape is bound at 159m, the tape feed speed is 6111+1/S at 12H2. The tape feed rate therefore depends on the diameter of the capstan and does not depend on a fixed bay. Also, tgoorpm
The drum rotational speed, for example, 1/10000 frequency division, etc., may be changed depending on the design of the device, but is not fixed. Now, 44, which can support a plurality of sampling frequencies with the above configuration, will be described below. Please refer to Figure 6r. Sampling frequency: Ps (Hz) Number of fenced bits: Ql) (bit). Number of audio channels: 011 Redundancy: C. If the data bit rate is 2 and the information waveform per track is Qi)
XC, X6G FS Tape speed VT, track pitch tp, ) Rack tilt angle θ If the track length and linear recording density are d, then the track length and linear recording density are d.
(4) Relative velocity between tape and head (Vll, drum diameter tφ
If so. (5) If the peripheral speed of the drum is iVd, then vd=φπ×τi ti
The track depth σ is the lead angle θ. Then, Vd Here, j〒 is from the formula 131161, and when n is set, Llh%
ul ~(81 formula 1c$"Ite linear +'liJ d
li'ffi <.・Number of quantization bits Qb knee > i2 (including use as a slot) ・Number of audio channels Cb: # ・Redundancy C,:# ・Number of heads H: # ・Recording density d: 〃 = per track Information processing: Let us consider the case where the sampling frequency & Fsk are changed under the above conditions. ■ From 1 set, data pit rail l-K it Fs
Take t which is proportional to K. ■ From formula 8, tape 4 degrees vT is the number of drum rotations (1?)
■ From Equation 4, the track length is a constant value. From Equation 6, the burning speed VH is proportional to the drum rotation speed N. From Equation 6, the drum circumferential speed Vd is proportional to the drum rotation speed. ■ +71 (Formula 81 19. Track inclination θ is constant t
And 9, Fs? Even if rR is achieved, the head trajectory does not change. In summary, quantization at multiple sampling frequencies n
When recording and reproducing the signal t1 with the same recording linear density and the same tape pattern format - (A) Change the drum rotation speed t in proportion to the sampling frequency (B) Change the tape feed speed t in proportion to the sampling frequency (C) Recording/playback on tape V-1- is proportional to the sampling frequency A device compatible with a plurality of sampling frequencies can be obtained with only the above eight points. As an example, FS=48KH2+Nt=181111
1pn4 When VT1=6ms/8 k F S =
When switching to 82 K II z, N, = X1
800=120+1rpm, v-cho, = 4-Fxe=
4/8 is good. In addition, in the above example, F s = 48 K HZ k
82K) IZ [Although this has been explained above, the protrusion can be performed in a similar manner to any sampling frequency, including the case of 44.1KH2. Although it has been explained that the drum rotational speed and the tape feed rate Q1 are controlled by frequency division of the master clock, a speed regulating mechanism may be provided to switch to a preset speed. Furthermore, a synthesizer-type lock generator can also be used. [Effects of the Invention] As described above, according to the present invention, for an apparatus corresponding to a sampling frequency of 1 L, a means for varying the drum rotational speed and tape feeding speed proportional to the sampling frequency is provided. Therefore, the device can be made at a low cost, with high accuracy, and the recording linear density can be made the same, so the sampling frequency can be changed. Is the recording and playback time the same even if the tape length is lowered? It has the effect of being able to last a long time. Brief explanation of the drawings Figure 1 is a block diagram showing the general configuration of a rotary head type recording/reproducing device using the PCM transmission system. Figure 2 is a diagram showing the sampling frequency FS = 48 KHz and drum rotation speed N = 180 degrees.
rpm, 2 to 7 do 17) A signal configuration diagram showing a 17L/-m configuration, FIG. 8 is a tape pattern diagram when recording on a magnetic tape, and FIG. 4H is an embodiment of this invention? FIG. 5 is a block diagram showing a clock frequency dividing circuit embodying the present invention. FIG. 6 is a tape format configuration diagram showing a tape format. In the figure, % (8) is the drum, (lυ is the capstan, haze is the master clock circuit % (1@ is the servo circuit, (7)
is a clock division circuit, (2LIQII4 is a separate n frequency divider. In the figure, the same reference numerals indicate the same or equivalent parts. I: tθg/h (Fig. 5

Claims (5)

[Claims] (1) In a device that performs recording and playback by responding to multiple sampling frequencies, when switching from the first sampling frequency to the second sampling frequency, the drum rotational speed and tape A rotary head type recording and reproducing device characterized by a groove bottom that changes the feed speed. (2) When switching the sampling frequency to 1k't,
2. A multi-rotating head type recording/writing device according to claim 1, wherein the master clock is fully controlled and the drum rotational speed and tape feeding speed are controlled in accordance with the frequency ratio. (3) Claim 2 of the Patent FF characterized in that the means for controlling the master clock is switching of a vibrator.
The rotary head type recording/reproducing device as described in . (4) Control of the master clock (Iil1) characterized in that the means is based on frequency synthesis;
2. The rotary head type brass reproducing device according to item 2. (5) Claim 1, characterized in that a deceleration mechanism is provided that switches the drum rotation speed and tape feeding speed to preset values when the sampling frequency is switched. A rotating head type recording and reproducing device.