RU2759753C1 - Method for measuring and indicating the frequency for an fm tuner and device for its implementation - Google Patents

Abstract

FIELD: radio equipment.

SUBSTANCE: invention relates to a method for measuring the frequency of the received signal for an analog tuner. To do this, a method is proposed that includes obtaining analog information about the tuning frequency of the tuner, its processing and indication, while the initial information about the tuning frequency is the capacitance value of the varicap controlled by a variable tuning resistor of the tuner, the variable voltage at which is converted by analog-to-digital conversion into a code followed by a functional conversion, which is transmitted to the display in the form of an approximated dependence of the frequency on the capacitance of the varicap to indicate the received frequency and voicing it in a speech synthesizer. A device for implementing the method is also proposed.

EFFECT: increase in the accuracy of tuning the radio.

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Description

The proposed method relates to radio engineering and can be used in radio receivers with single-chip analog tuners, in which tuning is carried out by changing the capacity of the varicap.

Recently, single-chip tuners have found widespread use in manufactured radio receivers. For this, both in our country microcircuits K174XA34, K174XA42, KS1066XA1 and others are produced, and abroad TDA7000, TDA7010, TDA7021, etc. voltage variable tuning resistor, makes it impossible to identify the frequency of the received stations. This was one of the reasons that the appearance of modern receivers with such tuners is stylized in antiquity by the introduction of old scales with arrows, the movement of which is produced by a mechanical drive from a variable tuning resistor.

Thus, in order to increase the functionality of modern radio receivers using tuners in which tuning is carried out by changing the capacity of the varicap, this method of measuring and indicating frequency is proposed, which increases the accuracy of tuning and its digital and speech visualization.

The essence of the proposed method is as follows. A method for measuring the frequency of the received signal for an analog tuner is proposed, which includes obtaining analog information about the tuning frequency of the tuner, processing and displaying it, characterized in that the initial information about the tuning frequency is the value of the varicap capacitance controlled by a variable tuning resistor of the tuner, the variable voltage at which is converted analog-to-digital conversion into a code with subsequent functional conversion, which in the form of an approximated dependence of the frequency on the capacity of the varicap is transmitted to the display to indicate the received frequency and sound it in the speech synthesizer.

All this makes it possible to realize effective tuning of the radio receiver with digital and sound frequency indication without mechanical hands and old scales.

Also, the goal for the implementation of the proposed method is achieved by the fact that an ADC, a programmable interface unit on a microcontroller or FPGA, an indication module, and a speech synthesizer are added to the device, which includes an analog tuner, the varicap capacity of which is changed using a variable tuning resistor and a stabilized power supply. with a speaker, and the output connected to the varicap of the variable tuning resistor is connected through the ADC to the programmable interface unit, and the inputs of the display module and the control input of the speech synthesizer are connected directly to the outputs of the interface unit, while the audio signal output of the speech synthesizer is connected to the speaker. Such a device makes it possible to fully implement the proposed method for measuring and indicating the frequency received by the tuner.

The introduction of an ADC and a programmable interface unit makes it possible to convert the voltage controlling the varicap capacitance into a code using an ADC with its subsequent conversion into a frequency code in a programmable interface unit, which generates a control code command to the speech synthesizer and is displayed on the digital display of the indication module.

A speech synthesizer is introduced to convert information about the measured frequency into a speech signal transmitted through a speaker.

All of these distinctive features make it possible to implement the proposed method for measuring and indicating the frequency of an analog tuner.

FIG. 1 shows a block diagram of the proposed device that implements the proposed method. The device contains (see Fig. 1) a tuner 1 with a varicap and a variable tuning resistor 2, an ADC 3, a programmable interface unit 4, a stabilized power supply 5, an indication module 6, a speech synthesizer 7 with a speaker 8.

The practical implementation of this device is carried out according to known schemes using a tuner 1, for example, the TDA7000 type from Philips [1] (domestic analogue KS1066XA1). As a varicap, you can use KV121A [2], for a variable adjustment resistor 2, a standard 100 kΩ potentiometer of the SP3-36 type is used, the display module 6 is made, for example, on a single-line liquid crystal display, a 10-bit ADC 3 can be, for example, K1113PV1A, a programmable interface unit 4 is made on a Microchip microcontroller or FPGA, for example, from Altera CYCLON IV, which converts the voltage code into a frequency code supplied to the indicator and speech synthesizer. The speech synthesizer 7 is made on the ISD1210 chip of the ChipCoder series from Winbond Electronics, the stabilized power supply 5 on the AMS1117 chip.

Let's consider the operation of the device. After turning on the stabilized power supply 5, a supply voltage is supplied to the device and to the upper terminal of the variable tuning resistor 2. Tuner 1 is initialized, the variable voltage is read from the output of the variable tuning resistor 2 (this voltage changes the capacitance of the varicap) and converted into code using the ADC 3. Then the voltage code is converted into a liquid crystal code using an approximating function that is stitched into the program of the microcontroller or FPGA of the interface unit 4 display 6 and is reproduced by speech synthesizer 7 using speaker 8.

Before programming the microcontroller or FPGA, the dependence of the voltage at the ADC input on the frequency of the received stations by the control receiver is measured. This is done to find an approximating function of the dependence of the frequency on the voltage applied to the varicap, for example, using a linear approximation. This function is used to convert ADC code to frequency code. Taking into account this formula and the type of display and speech synthesizer used, a microcontroller or FPGA is programmed.

Operation of the prototype device using the TDA7000 FM tuner confirmed the advantages of this effective technology for measuring and indicating the received frequency, increasing the functional and operational capabilities of the FM radio receiver.

Sources of information

1. Single-chip FM tuner from Philips TDA7000 data sheet https://www.alldatasheet.com/datasheet-pdf/pdf/19411/PHILIPS/TDA7000.html

2. Varicaps KB121A. Characteristics, https: //eandе.ru/pdf/diod/kv121.pdf

Claims (2)

1. A method for measuring the frequency of the received signal for an analog tuner, including obtaining analog information about the tuning frequency of the tuner, processing and displaying it, characterized in that the initial information about the tuning frequency is the value of the varicap capacitance controlled by the variable tuning resistor of the tuner, the variable voltage on which is converted by analog-to-digital conversion into a code with subsequent functional conversion, which in the form of an approximated dependence of the frequency on the capacity of the varicap is transmitted to the display to indicate the received frequency and sound it in the speech synthesizer. 2. A device for implementing the method according to claim 1 of the formula, including an analog tuner, a varicap, the capacity of which is changed using a variable tuning resistor, and a stabilized power supply, characterized in that it additionally contains an ADC, a programmable interface unit on a microcontroller or FPGA, a module indication and a speech synthesizer with a speaker, and the output connected to the varicap of the variable tuning resistor is connected to the interface unit through the ADC, and the inputs of the display module and the control input of the speech synthesizer are connected directly to the outputs of the interface unit, while the audio signal output of the speech synthesizer is connected to the speaker ...

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