JPS58224411A - Recording and reproducing device of fm broadcasting signal - Google Patents

Abstract

PURPOSE:To attain long-time recording and to reduce deterioration of sound quality due to the long-time recording by recording a stereophonic composite signal (voice signal) transmitted from an FM broadcase station in a video track of a video tape recorder and reproducing the recorded contents. CONSTITUTION:A stereophonic composite signal A after FM detection is outputted from an FM tuner 1 and a transistor (TR) Q1 is switched by an output signal F from a voltage controlling oscillator 2. An output signal D from a synchronizing signal generator 3 switches a TR Q2 and also changes the output level on the lower side of the TR Q1. Variable resistors VR1, VR2 adjust switched signal levels respectively. The impedance of an input signal B to a VTR 5 is matched by a buffer amplifier 4. The output signal C of the VTR 5 is applied to an output terminal 8 through a limiter circuit 6 and a frequency converting circuit 7 and connected to the antenna terminal of an FM tuner 1 or an intermediate frequency amplifying part. Thus long-time recording is performed and the deterioration of sound quality can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an FM broadcast signal recording and reproducing device.

Fixed-head tape recorders have been the most popular means of recording audio signals, and when recording for a particularly long time, the sound quality is affected by running a very long tape at low speed. to degrade. Considering the purpose of use of a consumer audio signal recorder, recording from a disc record, live recording, recording from FM broadcasting, etc. can be considered. Among these, disc records, live recordings, etc.
1. Time is limited, and a general audio recorder is sufficient, but especially when recording FM broadcasts for a long time and dubbing them all later, the sound quality deteriorates considerably due to recording once. do.

Therefore, an object of the present invention is to enable long-term self-recording of FM broadcasts while minimizing deterioration in sound quality.
By recording a stereo composite signal (audio signal) transmitted from a broadcasting station and reproducing it in its entirety, it is possible to record for a long time and to reduce the deterioration in sound quality caused by long-time recording.

An embodiment of the present invention will be explained based on an example.

In FIG. 1, reference numeral 1 denotes an FM tuner (receiver), which outputs as an output signal A a stereo composite signal after FM detection (or an audio 'IN signal if it is not a stereo broadcast). 2 is a voltage controlled oscillator, 3 is a synchronous signal generator, and Ql is a transistor switched by the output signal F of the voltage controlled oscillator 2. Q2 is a transistor that is switched by the output signal from the synchronization signal generator 3, and the transistor Q
The switching output level of the lower N (the upper side or both sides may be used) of □ is changed according to the output signal. R
ENG, VRYO and VR2fli are each for voltage division,
VR is a variable resistor that adjusts the signal level t-n switched by transistor Q1, ■, r/i is a variable resistor that adjusts the signal level switched by transistor Q2, R1 is a fixed resistor, and 10V is a positive power supply. , -■ is a negative power supply. Reference numeral 4 denotes a bumper amplifier, which is used for impedance matching of the input signal B of the home video tape recorder 50. C is an output signal of the home video tape recorder 5, 6 is a 172 circuit, 7 is a frequency conversion circuit or a frequency multiplication circuit, and 8 is an ID output terminal, which is connected to the antenna terminal or intermediate frequency amplification section of the FMf Yuna 1. .

A detailed explanation will be given for each block.

In order to record the entire signal on the video trunk of the home video tape recorder 5, since a rotating head is used, a pulse with a periodic sound equivalent to the vertical synchronization signal used in a television receiver is superimposed on the N-recording signal. Otherwise, even if the signals are recorded on the magnetic tape, they will not be synchronized during playback, causing noise.

- First, an output signal A such as a detected stereo composite signal is output from the FM team 1. The frequency band of this output signal A is approximately the audio frequency ~53 KHz, and the frequency oscillated by the accompanying voltage controlled oscillator 2 (which also performs frequency modulation at the same time) is i! Even the maximum frequency of 53 KHz in the band indicated by tI is a high frequency (for example, about I MHz) that allows sufficient frequency modulation. The reason for using this voltage controlled oscillator 2 is that the frequency of the voltage controlled oscillator 2 changes depending on the amplitude of the stereo composite signal, and the configuration is simple to extract it as a frequency modulated wave.
A filter may be inserted between the cheese 1 and the voltage controlled oscillator 2, through which only the stereo composite signal passes. The above voltage controlled oscillator 2 is a dedicated IC-? Since Kashira's (5) circuit has been proposed, we will use them.

Next, the output signal F of this voltage controlled oscillator 2 (Fig. 2)
As an input to the transistor Q, the collector and emitter of the transistor Q□ are switched. At the same time, the output signal D (approximately 60 Hz pulse: Fig. M2) from the synchronizing signal generator 3 is applied to the transistor Q2, and the transistor Q2 is switched. At this time, the waveform of the output signal E of the transistor Q0 is the same as that of the variable resistor VR□. Fixed resistor R1, variable resistor vR2 and transistor Q+0
The switching conditions in step 2 determine the frequency, the level of the 14-wave signal, and the synchronization signal.

The highest potential of the output signal E becomes a potential E' which is almost the same as +V when the transistor Q is on. The lowest potential of the output signal MH is p when the transistor Q is off and when the transistor O is on.

E at about 11t at that time is (the reference point of the potential difference is the 1V point). Further, the potential E at the intermediate point (6) is when both transistors Q□ and Q2 are off, and the potential E is as follows (reference point 6, -V point with an 11-point difference).

Therefore, the level centration of the frequency modulated wave can be made by the variable resistor VR, and the level centration of the p synchronization signal can be made by the variable resistor vR2. This output signal E is sent to the buffer amplifier 4.
The input impedance is matched with respect to the home video tape recorder 5, and the input is input to the sandwich input terminal of the home video tape recorder 5, and the signal is input to the video trunk of the magnetic tape via the rotary head of the home video tape recorder 5. Record hr'2.

Therefore, during playback, the output signal Ci1. output from the video output terminal of the home video tape recorder 5. Since it is the same as the waveform of the output signal E and it is necessary to remove only the synchronizing signal from it, the waveform of the signal G is the same as that of the signal F. (same as the waveform), and when added to the frequency conversion circuit or multiplier circuit 7, a high frequency output is obtained from the output terminal 8.

Here, the output signal from output terminal 8 is connected to a commercially available FM tuner.
The first method is F
When it is inserted into the antenna input terminal of M-chie 1, it is simpler to use a frequency conversion circuit as 7. For example, if the signal frequency of the output from the home video tape recorder 5 is I MHz, when mixed with the FM broadcast band or a frequency near C, for example, the local oscillation frequency of BO MHz, the signal frequency is output to the output terminal as 79 MHz or 81 MHz. 8 is output.

Connect it to or bring it close to the antenna input end of the FM tune 1 to set the tuning point of the FM tune 1 to 79 Ml(
z or 81 MHz.

Therefore, if a frequency multiplier circuit is used as 7, F
Intermediate frequency '4'fi of M team 1 (10,7MH
2) by inputting the same 1l of the FMf Yuna 1.
It can be played without taking t-. At this time, the center frequency of the output signal F is set to, for example, the field (approximately 1.19MHz
), it is possible to reproduce the signal by multiplying it by 9 and inputting it into the intermediate frequency amplification section.

Furthermore, even if all the multiplied waves are input to the antenna input terminal of the FMf zoomer 1, the multiplied waves may pass through the high frequency amplification section and mixing circuit section of the FM chainer 1 and be input to the intermediate frequency amplification section. This method may also be used.

Note that even when inputting to intermediate frequency #, a frequency conversion method may be used.

According to this embodiment, the home video tape recorder 5 can record the entire stereo composite signal H, that is, the signals for 2 channels, on one track of the video, and when playing back, the commercially available FM channel 1 (the same cheese used during recording), it is compatible with other FM cheeses. In addition, this circuit has a total of one FM team 1 (receiver)
Recording and reproducing can be simplified by incorporating it into the internal memory. An example of this is shown in FIG. First, 11 to 16 are the configuration of the FM tuner 1, where 11 is a high frequency amplification section, 12 is a mixing section,
13 is a local oscillation section, a 14-digit intermediate frequency amplification section, (9) 15 is an FM detection section, and 16 is a stereo composite signal demodulation section and a low frequency amplification section, which are standard components.

Reference numeral 17 denotes a circuit section surrounded by a dotted line in FIG. 1, where the input signal A in FIG. 1 corresponds to the input signal A in FIG. handle. 8 is an antenna, and L and R are output terminals for left and right signals, respectively.

In this example as well, as described above, the stereo composite signal of the FM detection section 15 is inputted to the circuit section 17 as the input signal A, the operation described above is performed, and the output signal is obtained at the output terminal 8.
This output signal is input to the intermediate frequency amplification section 14 or the high frequency field 11.

In addition, in order to prevent interference between the respective circuits when inputting this output signal (during playback) and when receiving FM broadcasting, turn on the switch at the input terminal of intermediate frequency amplification section 1@To 14 or high frequency amplification section 1. It's okay.

As described above, the FM broadcast signal recording and reproducing apparatus of the present invention includes an FM radio receiver, a frequency (10) frequency modulation circuit for detecting a detected output signal from the FM radio receiver, and a television receiver. a synchronization signal generator that generates a synchronization signal having a period equivalent to that of the vertical synchronization signal; a synchronization signal superimposition circuit that superimposes this synchronization signal on the output signal of the frequency modulation circuit; A video tape recorder that records on a video track, a synchronization signal removal circuit that completely removes the synchronization signal from the playback signal of the video tape recorder, and an output signal of the synchronization signal superimposition circuit that is sent to the front stage of the detection section of the FM radio receiver. Since it is fully equipped with a frequency matching circuit that supplies the correct frequency, it is possible to record FM broadcasts for long periods of time, and has the effect of reducing sound quality deterioration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram of each part thereof, and FIG. 3 is a circuit diagram of modification 9II. 1...FM Team, 21! LIC pressure controlled oscillator (frequency modulation circuit), 3 synchronous signal generator, 4... buffer amplifier, 5... household video tape recorder, 6... limiter circuit (synchronous signal removal circuit), 7... frequency conversion Circuit or multiplier circuit (J111 wave number compatible circuit), 8・-
・Output terminal, Q, Q2...Transistor (synchronous signal superimposition circuit) Agent Patent attorney Akio Miyai r ---
---Akebono-----Fight-----Shizuku 1-1-1 parable--] Direction 1st Flash Figure 3

Claims (1)

[Claims] (]) An FM radio receiver, a frequency modulation circuit that frequency-modulates a detection output signal from the FM radio receiver, and a synchronization having a period equivalent to the vertical synchronization signal of a television receiver. a synchronous signal generator for generating a signal; a synchronous signal superimposing circuit for superimposing the synchronous signal on the output signal of the frequency modulation circuit; a video tape recorder for recording the output signal of the synchronous signal superimposing circuit on a video track; Completely equipped with a sync signal removal circuit that removes the sync signal from the playback signal of the video tape recorder, and a frequency matching circuit that applies the output signal of the sync signal removal circuit to the front stage of the detection section of the FM radio receiver in a frequency-matched manner. FM broadcast signal recording and reproducing device. (2) The synchronization signal superimposition circuit includes a first transistor that is switched by the output signal of the frequency modulation circuit;
and a second transistor that is switched by the synchronization signal and changes only one of the upper and lower switching output levels of the first transistor in accordance with the synchronization signal. FM broadcast signal recording and reproducing device. (3) The frequency modulation circuit, the synchronization signal generator, the synchronization signal superimposition circuit, the video tape recorder, the synchronization signal removal circuit, and the frequency adaptation circuit are built into the FM radio receiver. Range 8 #I (1)
FM broadcast signal recording and reproducing device as described in 2.