JPH033973B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a pulse signal waveform shaping circuit that converts an encoded multi-bit digital signal indicating time, song number, etc. into a sine wave signal.

(b) Background technology Recently, in tape recorders, recording start time,
It is common practice to record a signal indicating the number of the recorded song or the recording position so that the recording start time and the like can be determined during playback. The recording start time, etc. is usually expressed as a 4-bit digital signal, and when recording starts, a built-in clock is operated to generate a 4-bit digital signal representing the time at that time, and the 4-bit digital signal is The recording is recorded on a tape via a magnetic head, and during playback, the 4-bit digital signal recorded on the tape is played back using the magnetic head, the reproduced 4-bit digital signal drives a display device, and the recording start time is set. The information is readable from the display device. The 4-bit digital signal representing the recording start time, etc. uses a low frequency of 10 to 15 Hz, which is outside the audible frequency range, but when recorded on tape, noise is generated during playback, which is not pleasing to the audible sense. This uses a half-wave signal obtained by simply shaping the digital signal to represent the above-mentioned recording start time, so the magnetic field on the tape being recorded changes in only one direction.
This is because the signal level becomes abrupt during reproduction. In order to eliminate this drawback, the encoded multi-bit digital signal representing the recording start time, song number, recording position, etc., that is, the 4-bit digital signal, is converted into one cycle of a sine wave signal, and the joint is All you have to do is set it to zero cross and record the sine wave signal.

(c) Means for Solving the Problems The present invention provides a pulse signal waveform shaping circuit that converts the encoded multi-bit digital signal used in such cases into a sine wave signal.

(d) Embodiments The present invention will be described below with reference to the drawings. 1 is a pulse signal generation circuit that generates a reference pulse signal, 2 is a frequency dividing circuit that divides the frequency of the pulse signal, and 3 is a frequency dividing circuit that divides the frequency of the pulse signal.
4 is a digital signal generation circuit that generates a coded multi-bit digital signal representing time, etc.; 4 is a parallel-to-serial conversion circuit that converts the multi-bit digital signal into a serial digital signal;
is a sine wave conversion circuit that converts the pulse signal into a sine wave signal, and is composed of two sets of integrating circuits connected in series. A transistor 6 switches the sine wave signal converted by the sine wave conversion circuit, and is turned on and off by the serial digital signal converted by the parallel to serial conversion circuit 4. 7 is an amplifier circuit,
8 is a magnetic head.

Next, the operation of the present invention will be explained. Now the reference pulse signal (second
Figure E) is generated. The pulse signal is converted into a sine wave signal (H in FIG. 2) by the sine wave conversion circuit 5. On the other hand, by operating the digital signal generation circuit 3, a 4-bit digital signal (second
Figures A, B, C, D) are generated. The figure shows an example of a recording start time of 8:12, and the 4-bit digital signal (A, B, C, D in Figure 2) is initially [1000], and the next timing is [0001]. ], and then becomes [0010] at the next timing. These parallel digital signals are controlled by a frequency-divided pulse signal obtained by dividing the pulse signal (Fig. 2 E) by L in a frequency divider circuit 2 in a parallel-to-serial conversion circuit 4, and are converted into a 1-bit serial digital signal. [100000010010] (FIG. 2F). This serial digital signal is inverted by the inverter 10 (FIG. 2G) and applied to the base of the transistor 6. The transistor 6 then receives the inverted serial digital signal. Since the signal (FIG. 2 G) is turned off only when the level is "0" and is turned on during other periods, the sine wave signal 1 is turned off only during one cycle of the sinusoidal signal when the transistor 6 is turned off. Therefore, the amplifier circuit 7 receives the serial digital signal (second
A sinusized one-cycle symbol signal (FIG. 2I) corresponding to FIG. F) is applied and amplified. Thereafter, it is added to the magnetic head 8 and recorded on the tape 9.

During reproduction, the symbol signal reproduced by the magnetic head 8 is converted into a serial digital signal, and the serial digital signal is further converted into a parallel digital signal (see FIG. 2A,
Since the 4-bit digital signals shown in B, C, and D) are obtained, the display device can be driven with the 4-bit digital signals to display the recording start time.

(E) Effects As described above, the pulse signal waveform shaping circuit of the present invention converts a reference pulse signal into a sine wave signal and adds it to a magnetic head as a recording signal. A multi-bit digital signal is generated, and the 4-bit digital signal is converted into a serial digital signal using a pulse signal whose frequency is divided by 1/2.The switch circuit is turned on and off using the serial digital signal whose frequency is divided by 1/2. Therefore, a recording signal converted into a one-cycle sine wave signal corresponding to the serial digital signal is supplied to the magnetic head. Therefore, when recording a multi-bit digital signal representing time, etc., it is possible to make a good recording without the noise that has been a problem in the past.

[Brief explanation of the drawing]

FIG. 1 is a pulse signal waveform shaping circuit diagram of the present invention.
FIG. 2 is a signal waveform diagram of each part of the present invention. DESCRIPTION OF SYMBOLS 1...Pulse signal generation circuit, 3...Digital signal, generation circuit, 4...Parallel-serial conversion circuit, 5...Sine wave conversion circuit, 6...Transistor.

Claims (1)

[Claims] 1 A pulse signal generation circuit that generates a reference pulse signal, a sine wave signal generation circuit that converts the pulse signal into a sine wave signal, and an encoded multi-bit digital signal that synchronizes with the pulse signal and represents information. A digital signal generating circuit that generates a digital signal, a frequency dividing circuit that divides the frequency of the pulse signal by 1/2, and a parallel-serial conversion that converts the multi-bit digital signal into a serial digital signal using the 1/2 frequency divided pulse signal. a switch circuit that is turned on and off by the serial digital signal, passes one cycle of the sine wave signal, and generates a recording signal converted into a sine wave signal of one cycle corresponding to the serial digital signal; A pulse signal waveform shaping circuit comprising a recording means for recording a signal.