JPS5843608A - Amplitude equalizer - Google Patents

Abstract

PURPOSE:To compensate a loss variation due to a temperature variation in the vicinity of a passing band of a filter having the sharp characteristics, by substituting a thermistor for a resistance of a time constant circuit part, and making it have the characteristics of temperature dependence. CONSTITUTION:A circuit having a thermistor Th is substituted for a resistance R11 or R12 of a time constant circuit, and the extent of variation of loss due to a temperature is controlled by suitably selecting a distribution of resistance Ra, Rb. Whether the circuit having the thirmistor Th is substituted for the resistance R11 or R12 is selected by watching a variation due to a temperature of loss in the vicinity of frequency corresponding to 50Hz of a broadcasting signal BPF. In this case, when a value of the resistance R12 becomes small, loss of 50Hz becomes small, and when a value of the resistance R11 becomes small, the loss of 50Hz become large. Accordingly, by taking notice of this point and also watching a direction of variation due to a temperature in the vicinity of frequency corresponding to 50Hz, whether the thermistor Th has a positive or negative temperature coefficient is selected so that the most suitable one can be obtained. In this way, not only the temperature characteristics but also the amplitude characteristics can be flattened, and also a fixed loss is scarcely increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chain equalizer for compensating loss fluctuations due to temperature changes in a P-wave device having steep characteristics.

Figure 111 shows the loss characteristics of a band r-wave filter (hereinafter referred to as BPF) for broadcast signals, and Figure 2 shows the loss characteristics due to temperature changes near the carrier wave of Figure 1 011PP.
・Sha! This example's pigeon house roars at the frequency indicating the lFF0 overband 0IIl end. 5.4 JSKHs, II ls, 5KHg
, f is the carrier layer tIIL number, which is 95.5 KHs in this example.
For example, when transmitting a broadcasting signal having a frequency band of 5G11-10 through a carrier line, as shown in Figure 1, the carrier wave frequency f@=iljs, 5KHm> is used at a high frequency l.
i60 db attenuation is required and within the passband (f ks
=95.45KHm~f*-85.5KHs) loss is 2. Below ah, a loss of 0.24b or less is required, including loss fluctuations due to temperature. Therefore, especially in the vicinity of the carrier frequency fe, an attenuation amount of 60 db is required with a 50H window separation, and the rise (rise) becomes particularly steep, resulting in PF. Even if the initial setting of PF is possible with high accuracy, due to the influence of a slight error in cancellation due to the temperature coefficient of the coil and capacitor and the variation of the temperature coefficient), the frequency fk The amount of attenuation changes depending on the temperature. In order to compensate for this variation in the amount of attenuation, the following two methods have conventionally been used. The first method is to adjust the temperature coefficient of the capacitor.

FIG. 3 is a circuit diagram showing a portion of the BPF for broadcast signals.

In the figure, SLa represents a coil, and C1 to C0 represent a conductor.

Since the temperature coefficient of Jiil Ll, L is approximately +150X10/degree, it is mainly conduit? C1, Cm and C
8. For C1, use a temperature coefficient of -150 x 10 - depending on the temperature coefficient of L1. , c, and lc are used, and the capacitance ratio v:I of capacitor C1 and capacitor Cm is adjusted while observing the actual capacitance-temperature characteristics of capacitor C- and capacitor C4. Also, the BPF is sealed after adjustment to prevent moisture. However, this method has the disadvantage that characteristics may vary due to aging effects after sealing and cannot be adjusted.

The second method uses variable equalization. Fourth
The figure is a block diagram when using variable equalization II (width equalizer), and Figure 6 is a circuit diagram of a conventional Bode type variable equalizer.
Figure 1 is a loss characteristic diagram showing the variation in attenuation in the case of Figure 5. In the figure, 1 is a Paude type voice specializer, (amplitude equalizer) 2 is a modulator, and 3 is a welfare broadcaster. Signal BPF, 4 is the demodulator, f is the carrier frequency, R1-R6 are the resistors, Ln is the coil, and C1 Hiro capacitor. When performing amplitude shaping of the broadcast signal BPF 3, use the carrier wave frequency f. It is better to perform the processing before the modulator 2 and after the demodulator 4, since the fractional band will be much wider. Therefore, the Paude type variable equalizer 1 is placed in the above-mentioned position.

Paude type variable equalizer IF! , when the resistance R in Fig. 5 is varied, as shown in Fig. 6 (at 50 Hm, where loss change becomes a problem with BPF3, when the resistance R8 is at the center value, the loss characteristic is flat with a constant loss j as shown in E). If the resistance R is small, the loss increases as shown in (c), and if the resistance Rs is large, the loss decreases as shown in (2).

For this reason, it is possible to replace the resistor R1 with a thermistor instead of a temperature-dependent resistor to compensate for loss fluctuations due to temperature changes in the BPF3. However, in this case, there are two “゛“
′″”°゛.

OBJECT OF THE INVENTION In order to eliminate the above-mentioned drawbacks, an amplitude equalizer is provided which can compensate for loss fluctuations due to temperature changes near the passband edge of an R-wave filter having steep characteristics, with almost no constant loss. It's on offer.

In order to achieve the above object, the present invention uses a bridge T-type constant resistance amplitude equalization (K), which replaces the resistance in the time constant circuit part with a thermistor having a negative or positive temperature coefficient, which is necessary for temperature compensation. F*l1lO with sharp shaping characteristics and steep modesty
Temperature Ii near the edge of the passband! It is characterized by compensating for loss fluctuations due to carbonization.

One embodiment of the present invention will be explained below according to the drawings.
' Figure 1 is a circuit diagram of a bridge T-type constant resistance amplitude equalizer according to an embodiment of the present invention, Figure 8 is a thermistor circuit diagram for adjusting the temperature coefficient, and Figure 9 is a temperature change in BPF for Hiro Broadcasting signals. FIG. 10 is a circuit diagram showing an example of clustering of bridging T-type constant resistance amplitude equalizers for loss shifting compensation near a carrier wave, and FIG. 10 shows loss characteristics in the case of the circuit of FIG. 9.

In the diagram, R0 is a resistance equal to 4$4 & impedance, L
~Rna resistance, Co is capacitor, t4a=zil,
Ra%Rb indicates resistance, 'rh indicates thermistor/Bridging T
For the same reason, the constant resistance amplitude equalizer is installed in the same place as the Bode type variable equalizer 1 shown in Fig. 4, and the high-pass type 4 shown in Fig. 7 is used. BPP for signals
As for the characteristic, the loss decreases at the sOHm@MkC) frequency, and the loss characteristic is set to be opposite to the loss characteristic of the amplitude equalizer described above.

Therefore, the resistor R11 or Rlm of the time constant circuit shown in FIG.
is replaced with a circuit having a thermistor Th as shown in FIG. 8, and the amount of change in loss due to temperature is controlled by appropriately selecting the distribution of resistors Ra5Rb.

Which of the resistors R and R4 should be fitted with a circuit having the thermistor Th is selected based on the temperature-related fluctuations in the loss near the 50-degree frequency of the BPF for broadcasting signals. In this case, if the value of the resistor R1 is small, the loss of 50 Ha is small, and if the resistance of the resistor R1 is small, the loss of 50 Ha is large. Therefore, we focused on this point and also
Select the thermistor Th with a positive or negative temperature coefficient, considering whether the fluctuation due to the temperature near the frequency corresponding to Hs is in the direction of A in Figure 2 or the direction of the mouth, and select the most suitable one. It is possible to flatten the amplitude characteristics by improving the temperature characteristics as a whole, and the increase in fixed loss can also be reduced. □This amplitude equalizer can be constructed with a simple circuit and does not have steep loss characteristics, so it may be an open type and can be modified as appropriate.

Figure 9 shows the data of the bridge T-type constant resistance swinging width vase used in 10EKII.

In Figure 9, the characteristic impedance is 4, 60-OΩ, so the resistance R0 in Figure 7 is 600Ω, Re-5, 56Ω, R1, = 6.
4.748Ω, R,, -15!14Ω, Ct+ xi
2.134 pF.

In Ll-4, 368H, the resistor Ru is a series circuit of a resistance of 94.50 and a thermistor Th having a negative temperature coefficient. The result of the measurement is that the resistance value of thermistor Th is 0 degrees C.
140 Ω at 25 degrees C, 60 Ω at 25 degrees C, 30 Ω at 45 degrees C.
It was Ω.

The loss characteristics shown in FIG. 10 are for the case of 28 degrees Celsius, and the loss characteristics shown in FIG. If it is 0 degrees C with a curtain at 50 Ha, it is 26 degrees C.
O,'15db11 degree loss increases compared to the case of .

Originally a broadcast BPF of 50 mm! Since the variation in loss due to temperature at fi is about this level, it is possible to sufficiently compensate for temperature variation.Also, the constant loss is 0.1 db 11 degrees, which is a value without any problem. It is an open type because its loss characteristics are not steep.

As explained in detail above, according to the present invention, the present invention is an open-type filter, and is capable of suppressing loss fluctuations due to temperature at the end of a pass band with steep characteristics, such as a BPF for broadcast signals used in a carrier line, and can reduce constant loss, including variations. This has the effect of flattening the surface area without increasing it.

[Brief explanation of the drawing]

Loss characteristics of BPF for 1I broadcast signal, first diagram is 1st
Figure 3 shows a circuit diagram of a part of the BPF for broadcasting signals, and Figure 4 shows the T-type constant resistance amplitude equalization using a variable variable vase. Figure 8 is a schematic diagram of the circuit for adjusting the temperature coefficient, and Figure 9 is a bridge T shape for compensating for loss fluctuations near the carrier wave due to temperature changes in the BPF for broadcast signals. A circuit diagram showing an example of the !J! resistance amplitude equalizer, and Fig. 10 shows the loss characteristics in the case of the circuit of Fig. 9. In the figure, fk%f is the frequency indicating both ends of the pass band of the IIPF. Isakazu, f @ Hiro transportation deceased Zhouyoukazu, Ll”wL4 Hiro; IL, CI
~G, is 37 capacitors, R1~Ru, Ra, nb,
Ro is a resistor, 'rhH+--star, l is a Bode type variable equalizer, 13 is a broadcast signal BPF, and 4 is a demodulator. One cycle frequency, number - Akira 3 Figure L + 4 Hikan 5 Akira 7 Figure 8 Procedural amendment (method) Showa year Month Day 57゜2,4 1. Indication of the incident Showa (Otsu year Permanent Application No. T4711) ?7 No. 3, Relationship with the case of the person making the amendment Patent applicant address 1015 Kamiodanaka, Nakahara-ku, Yozaki City, Kanagawa Prefecture (5
22) Name Fujitsu Limited 1 company 8, content of amendment Roa 11114 @ thing g (廄V thing 9 through R
at) l - room height 1't (1) This is a value of about 0.1 db, which is not a problem. Also, as shown in the data, it is a simple circuit and the loss characteristics are not steep, so it is an open type. As explained in detail above, the device vIK is an open type and has a steep characteristic like a BPF for broadcasting signals used in a carrier line. It has the effect of flattening the skin without increasing it. 4. Brief explanation of the drawings Figure 1 shows the loss characteristics of the BPF for broadcasting signals, and Figure 2 shows the loss characteristics of the BPF for broadcasting signals.
Figure 3 shows a circuit diagram showing a part of the BPF for broadcasting signals. Figure 4 is a block diagram when using a variable equalizer. Figure 5 6 is a circuit diagram of a conventional Bode type variable equalizer, FIG. 6 is a loss characteristic diagram showing variations in attenuation in the case of FIG. 5, and FIG. 7 is a bridge T-type constant resistor of an embodiment of the present invention. Circuit diagram of amplitude equalizer, No. 8
The figure shows a thermistor circuit diagram for adjusting the temperature coefficient, Figure 9 is a circuit diagram showing an example of a bridge T-type constant resistance oscillating flower vase 0jlIj11 for compensating for loss fluctuations near the carrier wave due to temperature changes in BPF for broadcast signals, and Figure 10. indicates the loss eat in the case of the circuit O of the e1gl. In the figure, fh, f・ are the frequencies indicating both ends of the BPFO passband, and fa is the carrier frequency -LI-IJ! coil, 0
1 to C11 are condensers, R1 to Rt** Rat R
b* R is resistance. 〒h indicates the thermistor, 1 indicates the Bode type variable equalizer, 2 indicates the modulator, 3 indicates the broadcast signal BPF, and 4 indicates the demodulator〇41

Claims (1)

[Claims] Bridge 111 A chain equalizer characterized in that in the T-type constant resistance amplitude equalization 11, the resistance of the time constant circuit portion is replaced with a nerstar, and the characteristic of 1w1 degree dependence is maintained.