JPH01317206A - Tape reproducing device - Google Patents

Abstract

PURPOSE:To shut out the hiss noises by detecting the breaks of the sound recording signals reproduced from a magnetic tape and switching the pass area of the output signal received from a reproducing part to a narrow area from a wide area. CONSTITUTION:The overall flat frequency characteristics are secured for the sound recording signal Sr reproduced from a magnetic tape 7 via a reproduction head part 1. The 1st and 2nd filters set in parallel to each other consists of the low pass filters 34. The cut-off frequency of the filter 34 is switched in two steps. A break detecting part 5 consists of a music interval detecting circuit 50 and outputs an H (high)-level signal for detection of the music intervals. Otherwise the part 5 outputs the L (low)-level signals. Since the circuit 50 detects a non-recorded part and reduces the cut-off frequency of the filter 34, the hiss noises are subut out.

Description

[Detailed Description of the Invention] [Summary] In a tape playback device having a playback head section and a playback section, when the playback section plays back a recording signal from the playback head section, the output signal from the playback section is a first filter that passes up to the first cutoff frequency; and a second cutoff frequency that is lower than the first cutoff frequency, and that transmits the output signal from the reproduction section up to the second cutoff frequency. By providing a second filter that passes through the recording, a break detecting section that detects a break in recording, and a switching section that switches from the first filter to the second filter each time the break detecting section detects a break, the recording It is possible to block the hiss noise generated from the magnetic tape at the break.

[Industrial application field]

The present invention relates to a tape reproducing device for reproducing recorded magnetic tape.

Generally, when a tape playback device plays back a recorded magnetic tape, such as a cassette tape, noise generated from the magnetic tape and containing many relatively high frequency components (usually referred to as hiss noise) is also played back. Therefore, it is not noticeable when playing back a part recorded by wiping the magnetic tape, but it becomes jarring when playing back an unrecorded part, such as a break between two recorded parts. be.

Therefore, there is a need for a tape playback device that can eliminate hiss noise generated from unrecorded areas on a magnetic tape.

[Conventional technology]

FIG. 4 is a schematic diagram of a conventional tape playback device. In this figure, a playback head section 1 from a recorded magnetic tape 7 is shown.
The recording signal sr detected via the reproducing section 2 is reproduced into an audio signal sa and outputted to the low-pass filter 3'. The low-pass filter 3' cuts off high frequency components of the audio signal s8 and outputs it as sound from a speaker via an amplifier, for example. Usually, the cutoff frequency of the low-pass filter 3' is determined by the sound quality and S/N at high frequencies of the audio signal Sr reproduced by the tape reproducing device.
It is set at the best point considering the ratio.

Also, depending on the tape playback device, the low pass filter 3
A Dolby circuit (not shown) is provided immediately after Sr to reduce the level of the high frequency of the audio signal Sr.
Improves N ratio.

[Problem to be solved by the invention]

In the above-mentioned tape reproducing apparatus, since the cutoff frequency of the low-pass filter 3' is fixed, there is a problem in that the hiss noise generated from the magnetic tape due to recording breaks cannot be blocked. Further, in a tape playback device equipped with a Dolby circuit in addition to the low-pass filter 3', there is a problem in that when the volume is increased, the Dolby circuit cannot completely remove hiss noise.

The present invention has been made in order to solve the above-mentioned problems, and in particular, it is an object of the present invention to provide a tape playback device capable of blocking hiss noise from a magnetic tape that occurs at breaks in recording. It is.

[Means to solve the problem]

FIG. 1 is a diagram showing the basic configuration of a tape playback device based on the present invention. In this figure, 1 is a playback head section;
The recorded signal Sr is reproduced from the recorded magnetic tape 7. 2
is a reproducing section, which reproduces the recorded signal S into an audio signal Sa. 3 is a first filter, which allows the output signal from the reproducing section 2 to pass up to the first cutoff frequency fc1.

4 is a second filter, which has a first cutoff frequency fc
A second cutoff frequency fc2 (f c2−
< f c2 (fc2 < fc1), and the second cutoff frequency fc2 for the output signal from the reproducing unit 2
to pass through. Reference numeral 5 denotes a break detecting section, which detects breaks in the recording signal Sr. Reference numeral 6 denotes a switching unit, which switches the first filter 3 every time the break detecting unit 5 detects a break.
to the second filter 4.

[For production]

The present invention detects a break in recording and switches the passband of the output signal from the playback section 2 from a wide band to a narrow band.

Specifically, the recording signal Sr reproduced from the magnetic tape via the reproduction head section 1 is reproduced by the reproduction section 2 into an audio signal S6. When the break detection section 5 detects a break in the recording signal Sr from the output signal from the playback section 2, it outputs a detection signal to the switching section 6, so that the switching section 6 switches the first filter 3 to the second filter. Switch to 4. As a result, the passband of the output signal from the reproduction section 2 ranges from the first cutoff frequency fcl to the second cutoff frequency fc.
2, that is, the passband switches from a wide range to a narrow range.

Thereby, it is possible to block the hiss noise generated from the magnetic tape at the breaks in the recording signal Sr.

〔Example〕

FIG. 2 is a diagram showing an embodiment of the present invention. In this figure, the playback unit 2 includes an equalizer 20, which compensates for the loss in the frequency characteristics of the recording signal Sr reproduced from the magnetic tape 7 (for example, a cassette tape) via the playback head unit 1, thereby creating an overall flat signal. Make it a frequency characteristic. The first filter 3 and the second filter 4 are composed of a low-pass filter 34, which is composed of a resistor R1 and capacitors CI and C2.
The cutoff frequency of is switched in two steps.

The break detection section 5 includes a song interval detection circuit 50, for example,
Usually used in tape players with a cue function,
This detects the gap between songs in order to locate the beginning of a recorded song. This inter-musical detection circuit 50 is composed of, for example, an integrating circuit and a comparing circuit, etc., and when detecting an intercostal interval, for example, the output signal from the noise reduction circuit 80 becomes H (high).
Outputs a level signal, otherwise L (low)
Outputs level signal. Note that this noise reduction circuit 80 serves to lower the level of the high frequency range of the output signal from the low-pass filter 34 and improve the S/N ratio. The switching section 6 consists of a transistor 60 and resistors 61 and 63, forming a semiconductor switch. The electrolytic capacitor 62 connected in parallel to the resistor 61 delays the on/off operation of the semiconductor switch, thereby preventing instantaneous switching from the first filter 3 to the second filter 4. Further, the output signal from the noise reduction circuit 80 is level-adjusted by a volume adjustment volume 90, amplified by a power amplification circuit 95, and output as sound from a speaker 100.

In this embodiment, a song interval detection circuit 50 detects an unrecorded portion in the recorded magnetic tape 7, and lowers the cutoff frequency of the low-pass filter 34 to cut off hiss noise generated by the unrecorded portion. be.

The operation of this embodiment will be explained below with reference to FIG.

(a) and (b) of this figure show the switching states of the cutoff frequency of the low-pass filter 34 during and between songs, respectively. In the state of (a), for example, when recorded music is being played back, the recording signal Sr played back from the magnetic tape 7 via the playback head unit 1 is input to the equalizer 20 and passed through the low-pass filter 34 to the Dolby It is input to circuit 80. The cutoff frequency fc1 of the low-pass filter at this time is set as follows. Therefore, the output signal S from the equalizer 20. Cutoff frequency f among the frequencies of U7
cl passes through the low-pass filter.

The signal S that passed through it. Noise is removed from U7 by the noise reduction circuit 80, and the sound as music is output from the speaker 00 via the volume volume 90 and the power amplification circuit 95. At this time, a part of the output signal from the noise reduction circuit 80 is inputted to the song interval detection circuit 50 . Song interval detection circuit 50
Based on this output signal, it is determined that the song is being played, and an L level signal is output to transistor low 0. Therefore, since the transistor 60 is held in an off state, the low-pass filter 34 outputs the output signal S0tl from the equalizer 20.
Of T, frequencies up to the above-mentioned cutoff frequency fcl are passed.

Next, when the song interval detection circuit 50 determines that the output signal from the noise reduction circuit 80 is between songs, the song interval detection circuit 50 outputs an H level signal and turns on the transistor 60. As a result, the cutoff frequency fc of the low-pass filter 34 is switched to the cutoff frequency fc2. The cutoff frequency fc2 at this time is as follows. Therefore, the output signal S from the equalizer 20. Of the frequencies of UT', frequencies up to the cutoff frequency fc2 pass through the low-pass filter 34. Since this cutoff frequency fc2 is lower than the above-mentioned cutoff frequency fcl, the passband becomes narrower than during the song (state (b)).

As a result, the hiss noise generated from the magnetic tape 7 at unrecorded portions is blocked, so that the listener does not hear harsh sounds between songs.

Note that in the above-mentioned song interval detection circuit 50, in order to detect a song interval, the determination is made based on the output signal from the noise reduction circuit 80, but the determination may be made based on the output signal from the equalizer 20.

〔Effect of the invention〕

As explained above, according to the present invention, a break in the recording signal that is played back from the magnetic tape via the playback head is detected, and the passband of the output signal from the playback unit is adjusted from a wide range. By switching to the narrow band, it is possible to block out the hiss noise generated from the magnetic tape, especially at the breaks in recording.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle configuration of a tape playback device based on the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a diagram explaining the operation of this embodiment, and FIG. 1 is a schematic configuration diagram of a conventional tape playback device. 1... Playback head section, 2... Playback section, 3...
1st filter, 4... Second filter, 5... Break detection section, 6... Switching section, Ll... First cutoff frequency, fc2... Second cutoff frequency.

Claims (1)

[Claims] 1. In a tape playback device having a playback section (2) that plays back a recording signal (Sr) from a playback head section (1), The first filter (which passes up to the cutoff frequency f_c_1 of
3); a second filter (4) that allows the output signal from the reproduction section (2) to pass up to a second cutoff frequency f_c_2 (f_c_2<f_c_1); The filter includes a break detecting section (5) for detecting a break, and a switching section (6) for switching from the first filter (3) to the second filter (4) each time the break detecting section (5) detects the break. A tape playback device characterized by: