JPS5857034B2 - transistor warmer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to obtain a transistor circuit that can perform multiplication of n signals.

In particular, as shown in FIGS. 1 and 2, the present invention includes a fixed lower drum 1, an upper drum 2 that rotates at a frame frequency, and a rotor that rotates integrally with the upper drum 2 at angular intervals of approximately 180°. It has magnetic heads 3a and 3b which are arranged opposite to each other, and the magnetic tape 4 is transported in a state where it is wound in an Ω-shape for more than half a turn around the circumferential surfaces of the lower drum 1 and the upper drum 2, and A rotating two-head type VTR that records video signals using magnetic heads 3a and 3b placed in the gap between the two.
Therefore, it is suitable for application when recording color television signals at high density.

To record a color television signal, it is separated into a luminance signal Y and a carrier color signal Sc to obtain an FM-modulated luminance signal YFM as shown in FIG. 3, and the carrier color signal Sc is converted to f.

This is done by converting the signal YFM and Cc to a low frequency to obtain a converted carrier color signal Cc, and recording one field of these signals YFM and Cc as one slanted track on a magnetic tape.

High-density recording of the signal YPM is made possible by making the azimuths of the working gaps g1 and g2 of the magnetic heads 3a and 3b different, as shown in FIG.

In other words, when recording is performed without providing any guard bands as shown in FIG. 5, for example, one of the magnetic heads 3a
Even if the magnetic head 3a scans not only the track Ta but also a part of the adjacent track Tb, azimuth loss occurs due to the high frequency of the signal YPM, and the magnetic head 3a is unable to extract almost any signal from the track Tb. There is almost no talk component, and no noise such as beat interference occurs.

In addition, in order to record the carrier color signal with high density, as shown in FIG. The color signal Sc is supplied to the converter 11, and the frequency f is output from the converter 11.

The converted carrier color signal Ca of 2 is obtained, and this signal Ca is supplied as it is to one input terminal a of the switch circuit 12, and is also supplied to the impark 13, and the signal -Ca obtained at the output of the inverter 13 is supplied to the switch circuit 12. The signal obtained at the output terminal C of the switch circuit 12 is supplied to the adder circuit 81 and added to the signal YFM.

Switch circuit 12 is controlled by a switching signal from terminal 14 shown in FIG.

This switching signal is formed from a horizontal synchronizing signal of frequency fh that is synchronously separated from a detection pulse indicating the rotational phase of the magnetic heads 3a and 3b. level,
In the next field where track Tb (7'') is formed by the magnetic head 3b, the level becomes high every horizontal period (H()).

When the switching signal is at a low level, the output terminal C of the switch circuit 12 is connected to the input terminal a, and when it is at a high level, the output terminal C is connected to the input terminal A.

Therefore, the signal Ca is recorded as is on the track Ta, and the signals Ca and -Ca are alternately recorded on the track Tb every horizontal period.

By doing this, if the carrier frequency of the signal Ca recorded on the track Ta is fca, then the track Tb
The signal Cb (-Ca, Ca, -Ca
, Ca...) has a carrier frequency of (fC,
11±fh/2) carrier frequency f.

It will belong to b.

That is, switching the signals Ca and -Ca in a horizontal period means that when the frequency of the signal Ca is fh/2, the relative level thereof is (+1) during one horizontal period, and the relative level is (+1) during the next horizontal period. is equivalent to multiplying by a rectangular wave whose value is (-1), and combining the two is equivalent to modulating the signal Ca with a rectangular wave signal of f11//2. No.

Therefore, the signal cb obtained by this balanced modulation has the frequency f of the original signal Ca.

Frequency f of (fCa±fh/2) for a.

b, and the frequencies fCa and f.

b are interleaved with each other.

The signal Ca recorded on tracks Ta and Tb in this way
By making the carrier frequencies of and cb different, the frequency distribution of the component of the signal Ca recorded on the track Ta becomes the 9th
The carrier frequency f as shown in Figure A.

The frequency distribution of the component of the signal cb recorded on the track Tb is equal to the carrier frequency f.

It exists for each horizontal scanning frequency fh with b as the center.

Therefore, when the magnetic head 3a scans the track Ta during reproduction, the crosstalk component Ch' generated when the magnetic head 3a also scans a part of the track Tb is a component of the signal Ca, as shown by the broken line in FIG. 9A. Similarly, when the magnetic head 3b scans the track Tb, the crosstalk component Ca' caused by also scanning a part of the rack Ta is shown by the broken line C in FIG. 9B. , it is inserted between the components of signal Cb.

In FIG. 6, 6 indicates a low-pass filter that separates the luminance signal Y, γ indicates an FM modulator, and the signal YFM from the FM modulator γ is supplied to the adder circuit 8.

FIG. 1 is a system diagram of the reproduction system, where 21 indicates a reproduction amplifier, 22 indicates a high-pass filter that separates an FM-modulated luminance signal, 23 indicates an FM demodulator, and 23 indicates a FM demodulator.
The luminance signal Y from the demodulator 23 is added to the carrier color signal Sc in the adding circuit 24, and a reproduced color television signal is obtained at the terminal 25.

The converted carrier color signals Ca and Cb are separated by a low-pass filter 26, and these signals Ca and Cb are supplied as they are to one input terminal a of the switch circuit 2γ, and are also supplied to the other input terminal via an inverter 28. Supplied.

The switch circuit 2γ is controlled in the same manner as the switch circuit 12 during recording by a switching signal shown in FIG. 8 from the terminal 29.

Therefore, when scanning the track Ta, the switch circuit 27
, the signal Ca and the crosstalk component Cb' distributed fh/2 deviated from the signal Ca are extracted as they are, and the track T
When scanning b, the signal Cb(-Ca, Ca.

Ca...) is converted into a signal Ca, and the crosstalk component Ca' is converted into a signal shifted by fh72 and extracted.

The output of the switch circuit 2γ is then supplied to the converter 30, from which carrier color signals Sea and Scb of frequency f are taken out.

Signals Sca and S obtained at the output of this converter 30
As shown in Figure 9 C and D, cb is distributed for each horizontal frequency fh with the frequency f as the center, and the crosstalk component is distributed fh/2 deviated from this, so there is a one horizontal period delay. Crosstalk components are removed by a comb filter 31 consisting of a circuit and an arithmetic circuit, and a carrier color signal Sc free of crosstalk components can be obtained as an output, as shown in FIG. 9E.

In the manner described above, color television signals can be recorded on a magnetic tape at high density.

The embodiment of the present invention is a converter 1 in the above recording method.
1. It is an object to obtain a transistor circuit that can independently realize the functions performed by the switch circuit 12, the inverter 13, or the switch circuit 2γ in the regeneration method, the inverter 28, and the converter 30.

Hereinafter, an example of the present invention will be explained with reference to FIG.

In FIG. 10, 41 surrounded by a broken line indicates a converter consisting of transistors Q1 to Q12, and output terminals 43 and 44 of the converter 41 are connected to transistors Q13 to Q1.
, 6 is connected to the switching circuit.

The emitters of transistors Ql and Q2 of converter 41 are connected in common, and transistors Q3 and Q4
The emitters of the two are connected in common, and a constant current source 42 that flows a constant current of 12 is connected to these two common connection points.

The transistors Q5 to Q8 are for differentially supplying the signal current from the first signal source 1 to the bases of the transistors Q1 and Q2 and the bases of the transistors Q3 and Q4, respectively.

That is, a pair of transistors Q5 and a set of objects Q7 and Q8
-C is differentially connected to the set of -C, and a constant current source 45 that flows a constant current of 11 is connected to the common emitter connection point.
A signal source V1 is connected to the bases of the transistors Q and the set of Q6 and the set of Q7 and Q8.

In addition, the transistors Q2 to Q12 transmit the signal current from the second signal source 2 to the bases of the transistors Q and Q2,
This is for supplying it differentially to the bases of transistors Q3 and Q4, respectively.

In such a configuration, the signal current flowing through each part is as shown in the figure.

X and y are from signal sources Vl and V2, respectively.

and transistor Q1t Q2 + Q3 t Q4
+ QQ +Q1o + The base-emitter voltage of Qtt and Q12 is
, TSvBE4νVBE1VBE1ol VBElo, and VBE, then 2 T .

However, in h-1, K is Boltzmann's constant, T is absolute temperature,
q is the charge amount of carriers, and 1s is the reverse saturation current between the base and emitter of each transistor.

Therefore, by substituting equations (1) to (4) into equation (9), and substituting equations (5) to (8) into equation 00), we get ax-(1-x) (1- a), x(1-b)-
(1-x) b, and therefore.

Therefore, the output current of transistor Q1 is (1-x)y12
Therefore, the output current of transistor Q4 is x(1y)I2
Therefore, the output current 1o1 appearing at the output terminal 43 is the sum of both, and the output current of the transistor Q2 is xyl 2
Therefore, the output current of transistor Q3 is (1-x)(1
y) Since it becomes I2, the output current io flowing to the output terminal 44
This is because 2 is the sum of both, and (1-x) and (i-y) are each expressed as "+Y".

In other words, the output signal is obtained by linearly multiplying the input signal.

The converter 41 described above may be the recording system converter 11 shown in FIG. 6 or the reproduction system converter 26 shown in FIG.
It can be done.

For example, in the case of a recording system, a carrier color signal Sc with a frequency f
is defined as a first signal source V1, and a carrier wave signal having a frequency f (3.58 MHz + foa in the case of the NTSC system) is defined as a second signal source v2.

As is clear from the αω equation described above, the converted carrier color signals -Ca and Ca of opposite phases are obtained at the output terminals 43 and 44.

One output terminal 43 of the converter 41 is connected to a common emitter connection point of transistors Q13 and Q14, and the other output terminal 44 is connected to a common emitter connection point of transistors Q15 and Qta.

A third signal source V3 is connected to the bases of the transistors Q13 and Qta, and a transistor Q14 is connected to the bases of the transistors Q13 and Qta.
A third signal source v3 is connected to the base of Q15.

The collectors of transistors Q13 and Q15 are commonly connected to form an output terminal 43, and the collectors of transistors Q15 and Q16 are commonly connected to form an output terminal 46.

This third signal source v3 is a pulse signal having the waveform shown in FIG. 8 described above.

With this configuration, the signal obtained at the output terminal 43 of the converter 41 expressed by equation (14) is designated as A, the signal obtained at the output terminal 44 expressed by equation (15) is designated as A, and the third signal source is Let Z be the signal supplied by V3 to the bases of transistors Q14 and Q15, and let J be the signal supplied to the bases of transistors Q13 and Q16, then an output of (AZ+AZ) will be obtained at output terminal 45.
6, an output of (AZ+AZ) is obtained.

Then, in one field where one track Ta is formed, Z becomes a high level, and the output terminal 45 receives A, that is, -Ca.
A, that is, Ca is obtained at the output terminal 46, and in one field where the next track Tb is formed, an output of Ca and -Ca is obtained every horizontal period. 45 and 46 are of opposite phase.

Therefore, by recording the output obtained at the output terminal 45 or 46 on the magnetic tape together with the FM-modulated luminance signal, it is possible to realize high-density recording of color television signals as described above.

FIG. 11 shows another example of the present invention, in which transistor Q13
The configuration of the switching circuit consisting of Q16 is the same as the above example, but as the converter 41 connected to this, transistors Q2'3 to Q26 are configured similarly to the switching circuit, and the emitters of transistors Q23 and Q24 are commonly connected. In this example, a configuration is used in which a signal current from the first signal source V1 is supplied in a differential manner to a common connection point of the emitters of the transistors Q2 and Q26 through the transistors Q2□ and Q28.

With this configuration, the current flowing through each part becomes as shown in the figure, and outputs similar to those of the converter 41 shown in FIG. 10 described above are obtained at the output terminals 43 and 44.

The examples shown in FIGS. 10 and 11 are combinations of a converter and a switching circuit, but the first and second signal sources obtained at the output terminals 43 and 44 of the converter 41 in FIG. The multiplied output may be further multiplied by the output of the third signal source V3.

For this purpose, the third signal source v3 may cause the transistors Q13 to Q16 to operate in a linear region.

In this case, as shown in FIG. 12, the third signal source 3 is supplied to the bases of differentially connected transistors Q29 and Q3o, and the signal current flowing to the respective collectors is passed through diodes 47 and 48. If the signal is converted into a non-linear signal and then supplied to the bases of the transistors Q13 to Q18, the linearity of the multiplication output can be further improved.

Further, in the example shown in FIG. 11, output terminal 4 of converter 41
If multiple stages of multiplication circuits connected in the same way as transistors Q23 to Q26 are connected in cascade to 3 and 44, the output terminal 4
5 and 46, the multiplication output of the signal sources v1 to vn of [ffi can be obtained.

According to the present invention described above, it is possible to easily obtain the product of n signals, there is no AC grounding part, fewer external terminals are required, and there is no fluctuation in the DC component of the output. Since it can be directly connected to the stage, it is suitable for IC implementation.

Further, if the converter circuit and the switching circuit are connected in series, the current consumption can be reduced compared to the case where both are configured separately.

If the present invention is applied to the recording or reproducing system of a VTR capable of recording color television signals at high density as mentioned at the beginning, there is an advantage that there is no need to separately provide an inverter, switch circuit, or converter.

[Brief explanation of drawings]

Figures 1 and 2 are block diagrams of a color VTR using the present invention, Figures 3 to 5 are route diagrams used to explain the same, and Figures 6 and 1 are system diagrams of the recording system and reproduction system, respectively. , FIG. 8 is a waveform diagram used to explain the recording system and reproduction system, FIG. 9 is a frequency spectrum diagram during recording and reproduction of the carrier color signal,
FIG. 10 is a connection diagram of one example of the present invention, and FIGS. 11 to 13 are connection diagrams of other examples of the present invention. Ta, T/b are tracks, 3a, 3b are magnetic heads, 11.30, 41 are converters, 12.27 is a switch circuit, 31 is a comb filter, Vl, V2 tV3
, vn-1, and Vn are signal sources, respectively.

Claims (1)

[Claims] 1 A pair of differential screws 11 connected in a double-balanced manner
a first analog signal source connected to an input terminal of each differential amplifier, a second analog signal source connected to a common terminal of each of the pair of differential amplifiers, A pair of differential amplifiers is connected to the common output terminal of the multiplication circuit, which obtains the multiplication output of the signals of the first analog signal source and the second analog signal source from the common output terminal of the pair of differential amplifiers. n double-balanced differential amplifier circuits each consisting of a dynamic amplifier are connected in series with their common terminal as the input side and their common output terminal as the output side; The input terminals of 1+2 (1=1, 2...
. . , n) input signal sources are differentially connected, and the n-th
The first, second .・
..., a transistor circuit configured to obtain a multiplication output of an n-th input signal.