JPS60143406A - Magnetic sound recording and reproducing device - Google Patents

Abstract

PURPOSE:To automatically set the most suitable sound recording bias current, sound recording level, and sound recording equalizer characteristic to magnetic tapes of any characteristics, by using a microcomputer of a stored program system. CONSTITUTION:To a sound recording bias current, initial data are outputted from a port output PD of a PIA3 and converted into a DC level by a D/A converter 30 and the bias current value of a bias oscillator 32 to a sound recording head 4 is controlled. A sound recording level is initialized to an appropriate value in such a way that data from another port output of the PIA3 are converted into a DC level by another converter 24 and a VCA22 is controlled through a buffer amplifier 23. A sound recording equalizer is initialized to an appropriate equalizer characteristic in such a way that data are outputted from a port PC of the PIA3 and converted into a DC level by a D/A converter 28 and a variable capacity circuit C is controlled through a buffer amplifier 27, and then, the appropriate equalizer characteristic is initialized at a sound recording equalizer controlling circuit 25 on the basis of the value of a coil L and the variable capacity circuit C.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a magnetic recording and reproducing device, and in particular to automatically setting the optimum recording bias current, optimum recording level, and optimum recording equalizer characteristics for magnetic tape of any characteristics. It was made so that it could be done.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

Following the flow shown in flowchart 1 in FIG. 7, the process from start to end will be explained in detail with reference to other drawings. The magnetic recording and playback device starts when the operator presses the AUTO key 100 on the operation panel in FIG. do. As shown in FIG. 2, a stored program type microcomputer is built in, and the contents of the ROM 34 containing old instructions are transferred to the CPU 34 via a path line 33.
reads out. Then, the first command (A) initializes the recording bias current, recording level, and recording equalizer.

That is, for the recording bias current, parallel binary initial data is output from the port output PD of the PIA 13, and D-
A (digital-to-analog) converter 30 converts it to a corresponding DC level. The DC level controls three impedance control circuits via the buffer amplifier 31, and controls the bias current value to the recording head 4 of the bias oscillator 32 which oscillates at 100 KH2, for example.

In this case, as shown in the bias current versus reference recording/playback horn in FIG. 3, data 3F'()-1") is output from Baud 1 to output PD of the PIA 13, and almost no recording bias current flows. , the initial setting of the recording level is
A suitable binary is sent via the boat output PB of PIA13.
The data is output and converted to DC level by the DA converter 24. The DC level is the buffer amplifier 23
The recording amplifier gain is set to an appropriate value. Similarly, for the initial setting of the recording equalizer, appropriate binary data is output from the boat output PC of the PIA 13 and converted to a DC level by the DA converter 28. The DC level controls the variable capacitance circuit via the buffer amplifier 27, and sets the capacitance value to an appropriate value. As a result, the recording equalizer control circuit 25 is set to have an appropriate equalizer characteristic based on the value of the coil [ and the value of the variable capacitance circuit C.

Next, the CPU 35 executes tape running start (B). As a result, a drive mechanism (not shown) becomes operational, rotates the reels 1 and 2, and the tape 12 reaches the recording head 4.
．． It slides on the playback head 3. Then, a selection command for the reference signal (for example, 333Hz) 16 is issued from the boat output P5 of the PIA 13, and the switch circuit 19 is controlled to select the 333Hz signal.
Create a Hz reference signal. A control command to turn on the switch circuit 6b is also issued from the port/output P2 of the PIA 13.

Next, the CPU 35 executes flow 1--t-1 (C).

That is, initial data 3 from the boat output PD of PIA 13
3331-I for a certain period of time with F(1-1) issued.
The Z reference signal is recorded and reproduced from the reproduction head 3.

The reproduced output is then rectified by a rectifier circuit 7 and converted into a blood flow level. The hold circuit 8 absorbs some level fluctuations in this value. Its output is applied to one end of the comparison input of comparator 10. Comparator 1
0 and the DA converter 11 constitute a part of a successive approximation type A-D (analog-to-digital) converter, and the comparator 10
The output of P is inverted when the output level of the hold circuit 8 and the level of the D-LA converter 11 match, and the inverted output is P
The binary data of the boat output PA applied to the boat power P1 of the IA 13 at that time results in an A-D converted value of the reproduction output level of the 333 Hz standard recording and reproduction signal. And this binary data is immediately stored in RAM3.
It is stored at address 8700 (1'') of 6. In addition, the DC level of the hold circuit 8 is directly A-D converted to the PIA 13.
The only thing that can be applied to the boat is lν.

When this operation is finished, a reset signal is instantaneously outputted from the boat output P3, and the output of the hold circuit 8 is reset by the reset 1-circuit 9, and then the binary data of the boat output PD is 3F(+-( 3E (T1), which is obtained by subtracting 1 from
(stored at address +-1>.

As described above, the binary data from the boat output PD is incremented by 1 one after another, and each time the playback signal level of 333H2 is converted to digital data, the store address is also added by 1, and the boat output PA is incremented by 1. The data is R
The binary data from the boat output PD is stored at each address on the AM36. In this embodiment, the binary data from the boat output PD is incremented by 1, but it may also be subtracted by 1 from the maximum value. , the value may be changed back and forth between the maximum and minimum values so as to approach the median value, and the state of change may be changed freely. In this embodiment, when the data is stored up to address 873F (H), that is, the bias current is divided into 64 parts from the minimum to the maximum, the data is stored.
The PU 35 executes the next instruction (D> in flowchart 1).

That is, read the data from address 8700 (H) to address <873F (+-1>), calculate the largest value among the data, or the value before or after it.Then, at that address, The binary data of the corresponding port output PD is saved to another register.

However, if a drop error 1 or an extreme drop in level is detected as a result of the calculation, an instruction is given to either start over from the beginning without saving it to the register as miss data, or to process the calculation as miss data.

Next, the instruction (E) of flow sheet 1 is executed.

That is, in this case, the purpose is to repeat the same thing three times and extract the average data, so the instructions (C) to (D) are executed three times.
) is repeated. It goes without saying that the larger the number of times, the more accurate data can be obtained, but this number is appropriately determined in consideration of the increase in search time.

Next, the CPU 35 executes the instruction (F> of flowchart 1).

That is, the boat output PD saved in each register
Three pieces of binary data are obtained, which are averaged to produce the average value of the binary data of the boat output PD. Then, the average value data is saved in a register as optimum bias current setting data. At the same time, the optimum recording bias current is fixed for subsequent adjustments.

When the recording bias current setting is completed, next
U35 executes the instruction (G) of 70-chip 17-t1.

That is, as shown in the recording level variable characteristics in Figure 4, first, 0O(H) data is output to the boat output PB of the PIA 13, the VCA 22 is controlled, and recording is performed with the 333 Hz recording level minimized. Reproduce. The DC-converted output of the reproduced output is applied to the comparator 10, while the binary data corresponding to the level is output to the boat output PA.
The D-A changed output is also applied to the other input terminal of the comparator 10, and the two are compared to determine whether matching data is applied to the boat output P1. - If rescue power is not obtained in port human power P3, Bo 1
- The data of the output PB is incremented by 1, (2) the recording level is increased in the CA 22, and the comparator 10 again compares the reference level with the recording/playback output to determine whether or not a matching output is obtained.

In this way, the boat output PB is increased by 1 at regular time intervals and compared each time, until a -rescue force is obtained. When a matching output is obtained at point X in Figure 4,
The port PB output data at that time is saved in a register. This is, in other words, the execution of command (1) in flowchart 1.

In this case as well, the method is not necessarily one in which the data is increased from 00 (1''), but can be freely changed, such as a method in which the data is decreased from 3F (+-1>).

Repeat the recording level search three times with the next execution command (J),
Each match data is stored in a register each time. In this case as well, it goes without saying that the greater the number of searches, the better.

The level setting data saved in register No. 3 by the next execution instruction (K) is averaged to determine the final recording level setting data. The data is then saved in the register and fixed as the output data of the boat output PB for the next recording equalizer adjustment.

In the next command (L), a 333H7 release signal is output from the boat output P5, and the switch circuit 19 is turned off by Δ.
Higher frequency reference signal (e.g. 10KHz) than boat output P6
A selection signal is issued to turn on the switch circuit 18. And the boat output Pc is the rebound data 00 (+-1)
It outputs and converts it from D to A to control a variable capacitance circuit whose capacitance changes according to a DC control signal. This variable capacitance circuit includes, for example, a circuit system using gain adjustment of an electronic variable capacitor circuit such as a Miller integration circuit. In this example, when the data is 00()-1>, the equivalent capacitance of the variable capacitance circuit is small, and as the data increases, the equivalent capacitance also increases.When the capacitance is small, the peaking resonance frequency is much higher than l0KH2. The characteristics are set such that the resonance frequency approaches 10 KHz as the capacitance value increases. In this case as well, the search is performed in the same manner as when setting the recording level. That is, the binary data of the boat output Pc is increased by 1 from 00 (T1), and each time the recording and playback output of 10KH2 is compared with the reference level by the comparator 11, and the matching output is the boat power P1.
Do this until it appears. Then, when the CPU 35 executes the instruction (M) and a matching output appears, the CPU 35 executes the instruction (N
) to save the binary data of the boat output PD to the register. Then, the CPU 35 executes the instruction (C) in the program in the same manner as the previous instructions (E) and (J). The data of the boat output Pc saved in the three registers is averaged by the instruction P to obtain the data of the optimum recording equalizer.

Further, this recording equalizer characteristic can be varied by dividing it into 64 sections in the same way as when adjusting the recording bias and recording level, but the accuracy can be further improved by increasing the number of divisions.

When the recording bias current, recording level, and recording equalizer characteristics are set in this way, the CPU 35 reads the command (Q) and stops the tape running, and also outputs the boat output P6.
A 10 KHz trial code reset control signal is output from the board output P2, and an off signal for the switch circuit 6b is output from the boat output P2.

Then, the operator presses the tape key 102 on FIG.
Press the upper 1 of the selection keys 103 to 9, and press the memory key 1.
When you press 04, all the data for the recording bias current, recording level, and recording equalizer for the magnetic tape used this time are stored in the appropriate address of the RAM 36. Once stored, all data can be saved by pressing this key at any time. Data can be recalled.

The manual switch 105 is a switch that works in conjunction with the switch 3wl, and resistors R1 to R3 can be freely selected.Some people may want to change the high frequency characteristics to some extent by varying the peaking characteristic Q. can be varied.

Further, the switch circuit 37 is a switch that mechanically detects whether or not there is a half tab on the chrome tape and turns it on and off. Further, in case some people really want to adjust the recording equalizer characteristics by themselves, a switch circuit 29 is provided which can be switched in conjunction with an external operation switch, and the volume VR can be adjusted by changing it.

In this way, when you press the normal recording button next time to start the recording operation, the playback output output terminal 14 is output from the boat output P1.
A control signal is output to turn on the switch circuit 6a, and an output signal from the boat output P4 turns on the switch circuit 20 to which the audio input terminal 15 is connected, and at the same time turns on the contacts of the switch circuit 40 as shown in the figure. By switching to the opposite side to the position, the sound quality can be changed by switching with the switch SW of the sound quality switching circuit 38.

Further, FIG. 6 shows a part of a specific circuit diagram designed in an actual experiment for the circuit block shown in FIG. 2 for reference.

(Effects of the Invention) As described above, since the present invention automatically adjusts the recording bias, recording level, and recording equalizer under computer control using a microprocessor, the adjustments can be made accurately and in a short time.

Also, C-M O3RA is stored in the memory where data is stored.
If you use a computer such as M and use a format that allows for discrete backup, the data will remain intact even if there is a power outage.

After setting τt+ in order N and 1.7Ω buffer 7, we set the recording level and finally adjusted the recording equalizer, so each adjustment is done once. This allows you to obtain highly reliable data.

Furthermore, when adjusting the recording bias current, if there is a dropout or extreme level fluctuation, it can be reliably detected and there will be no malfunction.

Furthermore, although it is a fully automatic adjustment function, it can also be manually varied, giving the listener a high degree of freedom.

In addition, since a processor such as a microcomputer is used, other post-mortem functions such as timers and tape counters can be controlled by simply increasing the software and its interface, making it possible to freely increase the functionality of the magnetic recording and playback device. It has many effects.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an operation panel used in the magnetic recording and reproducing device of the present invention, and FIG. 2 is a block diagram showing an embodiment of the present invention.
3 to 5 are characteristic diagrams for explaining the operation, FIG. 6 is a specific circuit diagram of FIG. 2, and FIG. 7 is a flowchart 17 showing the flow of the operation. 13...PIA 26...ROM 35...CPU 36...RA, M 39...Impedance control circuit patent applicant Pioneer Corporation @3 figure e〃θ-store 4I length color →E173F-o;'-)7
'OSA77 data → Continued from page 1 0 Author: Ishii Tsuyoshi, Tokorozawa City Hanazono 4, 0 author: Dai Takehata Shi, Tokorozawa City Hanazono 4

Claims (1)

[Claims] A means for setting an optimum recording bias current by varying the recording bias current at arbitrary time intervals, digitally storing each corresponding reference recording/playback signal, and calculating the recording bias current; Means for varying the level at arbitrary time intervals and comparing each corresponding reference recording and playback signal with the reference level to set the optimum recording level for the mid-low range; and means for varying the recording equalizer characteristics at arbitrary time intervals. ,
A magnetic recording and reproducing device comprising means for comparing each corresponding high-frequency reference recording and reproducing signal with a reference level to set optimum recording equalizer characteristics.