JPS5923633A - Display device for fm demodulation state - Google Patents

Abstract

PURPOSE:To facilitate operation on the basis of the extent and direction of detuning, by turning off a line light emission part in case of detuning, and turning on a red light emission part distant from the center according to the extent of the detuning. CONSTITUTION:If a center tuning frequency is in a frequency range FB or FC' a main D/A conveter 38 discriminates a DC component obtained by smoothing an FM detection output to generate a sink current at one of plural output terminals. Consequently, one of light emission parts 36-39, or 41-44 turns on to display the direction of a shift in tuning frequency. Then when the center tuning frequency fC is within its range + or -DELTAfC, a commutator 48 obtains a digit output corresponding to the line light emission part 40 to turn on the light emission part 40. At this time, the commutator 48 sends out a control signal for turning on a switch circuit 50, so a modulation of component EDISC is inputted to A/D converter 51 and 52, which generates sink currents to plural output terminals according to the deviation of the modulation component.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an FM demodulation status display device, and particularly to an FM demodulation status display device that can analyze and display the operating status of an FM signal demodulator over multiple items.

In general, as a display device for displaying the demodulation status of an FM signal demodulator, a 4" type as described below is known.

■Display that indicates all levels proportional to intermediate frequency amplifier output ■Display that indicates all remic output levels ■Display that indicates frequency discriminator output level ■Squelch indicator that indicates the state in which the noise level is suppressed As mentioned above Of the four types of indicators, the indicator described in (2) which indicates a level proportional to the output of the intermediate frequency amplifier, and the indicator which indicates the output level of the frequency discriminator described in (2) are often used. In communication devices, these indicators are often in the shape of a fingertip, and in FM radios and FM chits for receiving broadcasts, they are pointer-shaped, similar to those in communication devices.
Alternatively, the former (2) display may be a 3D display type, and the latter (2) display may be a zero center meter type.

Figure 1 shows the basic configuration of an FM demodulator.
2 is a high frequency amplifier or preamplifier. The output of this amplifier is input to mixer J3 and mixed with the output of local oscillator 14. The output of the mixer 13 is sent to the intermediate frequency amplifier 1
After being amplified, the signal is input to a limiting amplifier 16. The output of this limiting amplifier 16 is then input to a frequency discriminator 17.

Here, the four types of indicators that display the demodulation status are collectively shown: 21 is the indicator mentioned in the previous item ■, 22 is the indicator mentioned in the previous item ■, and 23 is the indicator mentioned in the previous item ■. Next item ■
The display device 24 is the display device mentioned in the previous item (■). Conventionally, one of the four types described above has been adopted.

Of the four types of indicators mentioned above, FIG. 2 shows a display 21 that displays a level proportional to the output of the intermediate frequency amplifier 16, and FIG. 3 shows a display that indicates the output level of the frequency discriminator 17. It is the vessel 24. The display 2 in FIG. 2 detects the output of the intermediate frequency amplifier 15 with a detector made up of a diode 21g, integrates it with an integrator made up of a capacitor 21b, and
This is a device that displays the output DC component using a fingernail-shaped display 21c. A light-emitting display section 21d may be used instead of the finger hook-shaped display section 21c. Indicator 24 in Figure 3
f, the output of the frequency discriminator 17 is connected to an integrating resistor, 74 a
, rN using the condenser 24b, and its (1
) Display the biological flow components using the zero point/pointer type display device 24c'''C
This shows the sac.

The relationship between the input level of the display devices 21 and 24 and the frequency is shown in FIG. 4. The display 21 shows whether the FM modulation range is centered around the center frequency fc. When there is No. 1, a constant DC component is regenerated, and the display 24 shows the medium 'L' component due to the FM detection characteristics.
? The frequency fc detection output is adjusted to zero torque, and a change in the output according to the degree of modulation of the frequency is detected to display →-deflection and -deviation.

However, according to the above-mentioned FM signal demodulation status display means, the display 21 shows - level (EBLT□1).
Since the above-mentioned DC reproduction only displays the required level input, it is difficult to judge whether the FM signal strictly corresponds to the center frequency or not. Furthermore, for the display 24, when obtaining FM tuning, for example, it is preferable to adjust the circumference so that the phase opening completely points to the zero center. There were some things that I didn't notice, but depending on the viewing angle of the display screen, the synchronization could be shifted from the zero center.

This invention has been made in view of the above circumstances, and it is possible to analyze and analyze the FM signal demodulation operation in more items, to make the tuning operation sound easier to understand, and furthermore, when the tuning is achieved, the FM modulation frequency deviation state It is an object of the present invention to provide an FM demodulation status production device that can also display FM demodulation conditions.

Embodiments of the present invention will be described below with reference to the drawings. First, the display section according to the present invention includes a plurality of light emitting sections formed by light emitting elements, 76 degrees 37.3 B, 39.41...
42, 43, 44°40. Light emitting part 3
6 to 39 (1, IJ where the FM reception frequency shifted in the negative direction)
The light emitting parts 41 to 44 are parts that change the light emitting position according to the deviation of the combination.
＼If there is a deviation, change the 119th IN according to the deviation.
).

Well, that's the part. And middle I+> rank 1#'/-v
The light emitting section 4o provided at L' is a portion that emits light when the center frequency is just below the FM reception frequency. The emitted light color of the light emitting section 40 is, for example, green, and the light emitting section 36 to 39.
41-44f are red.

Furthermore, the display section 45 emits green light on the base section 4o when the center frequency is one frequency away from FM reception, but in addition to this, the amount of frequency deviation during reception is also It can be displayed clearly. While maintaining the green light emission,

The red portions 36 to 39 and 41 to 44 light up or blink depending on the deviation situation K iQ. The light emission situation at this time is display weighted with respect to the modulation degree, for example, as shown in the following table.

The above display section is driven by a circuit configuration as shown in FIG. 6, the DC component (FBI, ) detected from the intermediate frequency output explained in FIG. 4 is input to the 1 input terminal 56, and the FM The detected modulation component (ED□me) is input.

The modulation component (E□.) is transmitted to a modulation component removal filter 47,
The signal is input to the switch circuit 50. Weird it! The J component removal filter 47 outputs a DC component corresponding to the manual modulation component. The small switch circuit 50 is a circuit that converts the human power modulation component to its output terminal in response to the control +11ri applied to the control terminal 50k. 49 is a positive base 1
In the %lx pressure generation section, analog-to-digital converter 48
, is a circuit that applies a positive reference voltage to the positive domain analog-to-digital converter 51.

Further, 53 is a negative reference voltage generation section, which includes an analog-to-digital converter 48 and a negative region analog-to-digital converter 52.
This is a circuit that applies a negative reference voltage to.

The analog-to-digital converter 4B, 51.52fJ1, which will be described in detail in FIGS. 7, 8, and 9, respectively, receives the DC component of the modulation component (E) manually and connects it to the terminal l5c. A positive reference voltage is input to terminal 48k, and a negative reference voltage is input to terminal 48RK. And this analog digital converter 4
Reference numeral 8 allows the contents of the nine digital outputs to be varied according to the input DC voltage level. Further, when the direct current voltage level is within the ±Δfc range of the FM center frequency f, this is determined and a control signal is output to the output terminal 48C. In this case, the switch circuit 5o derives the input modulation component (Dlsc) to the output terminal.The positive domain analog-digital converter 51 connects the terminal 51 with a positive reference voltage
A reference voltage is applied to the terminal 5Z11KOV, and the contents of the four digital signals can be varied according to the deviation of the input modulation component (EDl, c). The negative range analog-to-digital converter 52 has a negative reference voltage at a terminal 52AK and a negative reference voltage at a terminal 52B.
A reference voltage of 1 is applied, and each of the four digital outputs can be varied according to the deviation of the input modulation component (Enlge). Above analog-to-digital converter 48.51.52
The output data of is input to the signal synthesizer 54. This signal synthesizer 54 receives nine digit data [
xl.

x2. ...
Data of 47j points from ry1. y2゜ys,y
47' data from the analog-to-digital converter 52 r z 1 + * 2 + y 3 +z
4J is synthesized to display 9 digits of display data "d).

d2. d3. . . d9" and input this into the display section 45. 56, the DC component EIIL is at a predetermined level EI
This is a switch circuit that supplies power "ee" to the display section 45 when the voltage is higher than ILTII, thereby enabling the display operation to be performed.

The above display device has now undergone the same n"4 M'J tuning of the FM signal so that the tuning center frequency is in the frequency domain FA shown in Figure 4.
If it is outside the range of
Since ce is not applied, there is no display tj2 at all. Next, assuming that the RIIJ center frequency is in the FBI or FQ frequency range of section 4, section 1, the main analog-to-digital converter 48fi, II'M detection output is smoothed, the DC component is determined, and the 9 digits are determined. A sink current 1c is generated in the output whose fall is 1 among the outputs. Therefore, which one of the light emitting parts 36 to 39 or 41 to 44 emits light and in which direction the current tuning frequency is shifted is displayed in an easy-to-understand manner. At this time, since the switching circuit 50VJ and the control signal from the analog 7J-7 converter 48 are turned off, there is no output of each of the four outputs from the positive domain analog-to-digital converter 51 and the negative domain analog-to-digital converter 52.

Next, the tuning center frequency is determined by the difference Δf between the predetermined center frequencies fc
If they match within 0 (as shown in FIG. 4), the main analog-to-digital converter 48 obtains a digit output corresponding to the green light emitting section 40. Therefore, the green light emitting section 40 lights up.

On the other hand, at this time, the main analog-to-digital converter 48
Since a control signal for turning on the switch circuit 50 is obtained from
2, the modulation component Ise is input. The analog-to-digital converters 51, 52 produce sink currents on each of the four digit outputs depending on the deviation of the modulation component. For this purpose, the green light emitting section 40 lights up on the display section 45 to indicate that the tuning state is accurate, and
A plurality of red light-emitting parts can be turned on in a swinging manner to display the circumference σU number deviation situation.

FIG. 7 shows a specific example of the analogue nockle converter 48 shown in FIG.
A plurality of voltage dividing resistors ro are connected between B and B.

rl...r9 is connected, stop, negative reference 11L pressure -l
'ey+-e is divided into voltages. cl, C2,...C
9fJ, each voltage comparator, each voltage dividing resistor ``θ+
A divided voltage is applied to one of the input terminals corresponding to r1+...r9. That's right, voltage comparator C
Human power DNA of each other of C2...C9 48 D
The DC voltage from the previous filter 47 is commonly applied to Kt. Next, each voltage comparator c J T e 2 +
・Each output of C9 is inverter NVJ,
INV 2°... Corresponding NAND circuit NAND 1 via INV 9.

NAND Z, . . . are applied to the second input terminals of NAND 9. And each NAND circuit NAND 1
, NANI)2°...The output of the voltage comparator on the upper voltage side is applied to each other input terminal of the NAND 9. fc, but for NAND circuit NAND 9, the first. The output of the inverter INV 9 is commonly applied to the second input terminal, and each NAND circuit NAND 1
, NAND2.

...Each output of NAND 9 is used as a 9 digit output. In this circuit, each comparison output changes from positive to negative with its reference voltage as a critical point.

This output is logically ANDed with outputs of comparison values with successively higher-order reference voltages, and a specific comparator output is set to be valid data.

That is, the voltage at the terminal 480 is equal to the voltage dividing resistor 100 and the reference voltage 01.
If it is below, the voltage comparator eJ.

The outputs of c2...c9 are at high level. Therefore, the output terminals xl*x2+...x9 are at a high level, and no sink current is generated. When the voltage at terminal 480 is between reference voltages e1 and 02, the output of voltage comparator c is at a low level and 1! υ, the output of the NAND circuit NAND 1 generates a sink current.

Next, when the voltage at the terminal 48D is between the reference voltages e2 and e3, the output of the voltage comparator clrc2 becomes low level. Therefore, the output terminal x becomes low level due to the output of the voltage ratio converter C2 of which the first input of the NAND circuit NAND1 is at the upper level. As a result, no Kunck current is generated at the output terminal x1, and a sink ηL current is generated at the output terminal x2.

The outputs of the other 1115 voltage comparators remain at high level. In this way, as the higher level voltage comparators transition, any one of the output terminals x1 to X9 will generate a sink current. This becomes the drive current for the light emitting section.

FIG. 8 shows the positive domain analog digital converter 51 shown in FIG.
4 is provided between the positive reference voltage terminal er and the reference voltage of 0.sup.4 to generate divided reference 111.degree. voltages e01 to e04. Reference voltages eox~1304~ are applied to one input terminal of each of the corresponding voltage comparators COI~CO4. Then, the modulation component ED I from the switch circuit 50
Bc is commonly applied to the other input terminals of the alcohol 1 and the pressure comparators COI to CO4. With this, 6 tigers, LE
At the output terminals y1 to y4 of the comparators COJ to CO4, sink currents are generated sequentially as the voltage of the modulation component "'Disc increases. That is, now the input terminal 5JC
When the voltage of output terminal 71. is less than the reference voltage 001.
74 are all current and no sink current is generated. When the input terminal 61CL:D voltage falls between the reference voltage eO1 and the reference voltage eO2, a sink current is generated at the output terminal 701 of the pressure comparator CO1. (1) Force terminal y2
~y4 remains at a high level. Next, input terminal 5JC
When the M1 voltage is between the reference Ttf and pressure e02 and the reference voltage eO3, the output terminal y of the voltage comparator COI and CO2
A sink current is generated at the output terminals y3.1 and y2, and the output terminals y3.
y4 remains at high level. Input terminal 5 like this
1 box, output terminals y1 to y4 as pressure increases
A sink current will be generated in the direction.

FIG. 9 shows the negative region analog-to-digital converter 52 shown in FIG. 6, in which a series-connected voltage dividing resistor rlO=r14 is provided between the negative reference voltage -6r and the reference voltage QV.
Voltages ell to e14 are generated to the group C, which is increased by C. Load voltages f311 to e14 are applied to the corresponding L1 and one input terminal of each of the pressure comparators CI1 to C14, respectively.

Then, the modulation component EDltrc from the switch circuit 50
is the power-saving 11-mi comparator C1l~C through the input terminal 52C.
Now terminal 52 is applied commonly to each other input terminal of 14.
When the voltage at C is below the reference voltage eJJ, the output terminal z
1-oz 4 are all)-irrepel, and when the voltage at the terminal 52C falls between the reference voltage F311 and the reference voltage e12, the output terminal $ of the voltage comparator C1l occurs. 1 generates a sink current, and output terminals L2 to z4tj remain at high level. Next, when the voltage at the input terminal 52C falls between the reference voltage e12 and the reference voltage e13, the output terminal z of the voltage comparator C11°C12
1 + z 2, a sink current is generated at the output terminal z3.
v4 has up to )・Irepel's t. In this way, as the voltage at the input terminal 52C increases in the negative direction, 11
Sink currents can be generated in multiple terminals at the same time in the 11th orders z1 to z4.

FIG. 10 shows the signal synthesizer 54 and display section 45 shown in FIG.
is shown in detail. 1 to the input terminal of the signal synthesizer 54
~k17 has the analog-to-digital converter 4B, respectively.
, 51.52 output terminals x1 to x9, z1 to v4, yl
-y4 is connected, and resistors r21 to r37 are connected in series to each input terminal 1 to 77. The output terminals of resistors r21 and r30 are commonly connected to a composite output terminal j1.
The output terminal of the resistor r22er31 is connected to the composite output terminal j2, the resistor r23. The output terminal of r32 is the composite output terminal j
3. The output ends of the resistors r24+r33 are connected to the composite output terminal j4. Then, only the output end of the resistor r25 is independently connected to the output terminal j5. In addition, the output terminal of the resistor r26°r34 is the composite output terminal j6, and the resistor r27°r3
The output terminal of resistor r28°136 is connected to composite output terminal j8, and the output terminal of resistor r29°r37 is connected to composite output terminal j9. The output terminals j1 to j9 are connected to each cathode of the light emitting diodes D1 to D9. Also, light emitting diode I) J~
The anodes of D9 are commonly connected to the power supply terminal 415A. Therefore, among the input terminals k 1 to 9 of the synthesizer 54,
When a sink current is generated in any one of the corresponding light emitting diodes D1 to I) 9 (f'J), one of the corresponding light emitting diodes D1 to I)9 (f'J) emits light.
corresponds to the light emitting diodes I) 1 to 1]4, and the input terminals are 14 to lc 17 tJ: Light emitting diodes D6 to D9
It corresponds to Therefore, assuming that the tuning frequency matches the center frequency fc and a sink current is generated at the input terminal 5, causing the light emitting diode D5 to emit green light, as explained in FIG. The analog converter 51.52 digitally converts the modulation component ED I sc, so the output terminals y1~)'4177~z4,
A sink current is generated in the number corresponding to the modulation deviation.

As a result, in the display section 45, the display sections corresponding to the positive and negative frequency regions emit red light with the green light emitting point at the center.

If the modulation shift is wide, the red light emitting part will spread out, and if the modulation shift is small, it will approach the green light emitting part and shrink.

The present invention is not limited to the above embodiment, but may be configured as shown in FIG. 11.

That is, the same parts as in FIG. 6 will be described with the same reference numerals.
A DC component EBL obtained by detecting the intermediate frequency output is inputted to the DC component EBL. Furthermore, the output of the absolute value circuit 60 having a negative output polarity is applied to the negative region analog-to-digital converter 52. This absolute value circuit 60 is a circuit into which the modulation component EDI 80 from the switch circuit 50, which is turned on when the FM detection output is at the center frequency fe (within ±Δfe), is introduced. Since the modulation component has a component (bipolar signal) that shifts to the positive and negative regions as it is, the positive sign is converted by the absolute value circuit 60 with negative output polarity, and the analog/digital signal is converted into an analog/digital signal. input to converter 52;

The rest of the circuit configuration is the same as that of the embodiment shown in FIG. 6, so a description thereof will be omitted.

According to this embodiment, the display mode of the display unit 45 is different from that of the embodiment shown in FIG. That is, the tuning center frequency is now the first
If the frequency range is in the frequency range p'B or Fc shown in FIG.
Any one of 44 to 44 emits light. In this case, the DC component Ii:BL is at a high level and all the output terminals of the p1 analog bus converter 51 are generating sink currents, so all of the light emitting sections 41 to 44 are lit. Here, if the output terminal of the analog de soccle converter 48 that is generating a sink current corresponds to any one of the light emitting parts 41 to 44, the corresponding light emitting part ↓b The brightness is higher than other parts. At this time, display section 4
5, first, the tuning frequency is t in the area F human flesh in Figure 4.
Moreover, it can be recognized that the tuning center frequency is located in the light emitting part with high brightness.

Next, when the tuning center frequency is within ±Δfe of FIG. 4, the display of the frequency deviation situation is started. That is, since the switch circuit 50 is turned on, the modulation component EDI 80 is input to the analog-to-digital converter 52 via the absolute value circuit 60. The light emitting section 39 changes depending on the frequency shift due to the bending.
．． 36 will emit light in sequence.

As mentioned above, when performing a tuning operation on the FM frequency, this device turns off the green light emitting part if it is out of tune, and turns off the red light emitting part farther from the center depending on the amount of deviation. emits light. Therefore, the amount of deviation and its direction can be easily known, and the operation can be facilitated. When further synchronization is achieved, the green light emitting section lights up and the display row length of the red light emitting section is varied in accordance with the frequency shift, making it possible to display multiple elements.

As described above, the present invention can provide a high-quality FM demodulation status display device that can display a large number of display items.

[Brief explanation of drawings]

Figure 1 shows the demodulation status indicator 1'u'f of the FM demodulator.
The block diagram shown in Figures 2 and 3 does not show a part of the display in Figure 1, and Figure 4 does not show a part of the display in Figure 1.
FIG. 5 is a diagram showing each output characteristic of the M intermediate frequency amplifier and the frequency discriminator; FIG. 5 is an explanatory diagram of the display unit according to the present invention; FIG. Figures 7, 8, 9, and 10 are respectively circuit diagrams showing the same circuit as in Figure 6, and Figure 11 is an explanatory diagram showing another embodiment of the invention It is. 45...Display section, 47...Modulation component removal filter,
4B, 51.52...Analog-digital converter, 49
．． 53... Reference voltage generation section, 50... Switch circuit, 54... Signal synthesizer, 60... Absolute value circuit.

Claims (1)

[Claims] (Re) FM detecting the output of the FM intermediate frequency amplifier, and detecting a detection signal that changes in a first direction according to a negative shift in frequency, centered on a predetermined level detection output obtained during center frequency detection. a frequency discriminator that obtains a detection output that changes in a second direction according to the positive shift of the output and frequency, and a detection output of the frequency discrimination means that is input as a detection voltage via a modulation component removal filter, a first alarm-to-digital converter that obtains a detection output at any one terminal among a plurality of output terminals that distinguish between a magnitude range of the detected voltage by comparing the reference voltage of the detected voltage with the detected voltage; a display means having a light emitting section corresponding to a plurality of output terminals of the first analog-to-digital converting means, and causing the light emitting section corresponding to the output terminal formed with the terminal for obtaining the detection output to emit light; a switch circuit to which, when the predetermined level detection output at the time of center frequency detection is input to the digital conversion means, the output of the output terminal A for obtaining the detection output is added as a control signal; and the control signal is manually input to the switch circuit. Sometimes the above F derived from this switch circuit
It has a plurality of output terminals for dividing the ratio signal according to the frequency deviation of the M detection output, and the output from each output terminal can be made to correspond to each light emitting section of the display means to cause the light emitting section 9'C to emit light. and a second analog-to-digital conversion means. (2) The FM according to claim 1, wherein the display means is characterized in that the color of the light emitted by the light emitting section that emits light during the center frequency detection is different from that of the other light emitting sections.
Demodulation status display device. (3) The second analog-to-digital conversion means includes a positive-area analog-to-digital converter and a negative-area analog-to-digital converter to which the output of the switch circuit is commonly applied; The FM demodulation status display device according to claim 1 of the patent application, wherein each output terminal corresponds one-to-one to each different light emitting section of the display means. (4) The second analog-to-digital conversion means 1 includes an absolute value circuit to which the output of the switch circuit is applied, and a converted output of this absolute value circuit is applied, and each of the plurality of output terminals is connected to the light emitting section of the display means. A negative region analog-to-digital converter corresponding to about half of the light emitting parts and a detection output of the output of the FM intermediate frequency amplifier is added to the input terminal, and a plurality of output terminals are made to correspond to about half of the light emitting parts and the center frequency. 2. The FM demodulation status display device according to claim 1, further comprising a positive area analog-to-digital converter corresponding to the remaining light emitting parts excluding the light emitting part.