CN2393273Y

CN2393273Y - Broadcasting machine on train

Info

Publication number: CN2393273Y
Application number: CN 99213647
Authority: CN
Inventors: 邵未
Original assignee: HAIDA ELECTRONICS CO TIANJIN
Current assignee: HAIDA ELECTRONICS CO TIANJIN
Priority date: 1999-06-08
Filing date: 1999-06-08
Publication date: 2000-08-23
Anticipated expiration: 2009-06-08

Abstract

The utility model discloses a broadcasting machine on a train, which integrates sound record, sound play, sound collection and a digital tuning microprocessor. An amplitude modulation sound collection band adopts the technique of secondary frequency conversion and the analog of a subtracter; frequencies which are increased at the first frequency conversion are sent to a digital tuning system after subtracted, and the frequency lock is finished. The utility model realizes the reception mode of the secondary frequency conversion by using the existing first frequency conversion digital high harmony microprocessor. The utility model adopts the frequencies of first medium frequencies, so long waves to short waves are designed in a band. The circuit is simplified, so the utility model can meet the single-level machine index of broadcast receivers in China. The utility model is a broadcasting machine suitable for electrification trains.

Description

A kind of train broadcast transmitter

The utility model belongs to the broadcasting equipment of train.Specifically, it relates to recording, playback, radio reception and digital tuning microprocessor in the speech amplifier of one.

At present, domestic existing speech amplifier, in the amplitude modulation radio reception part, short-wave band receives the superhet that all adopts single-conversion, the defective of this circuit is, one, receptivity do not reach the index of government broadcasting receiver one-level machine standard, and its leading indicator can only reach secondary machine index, reach 20 microvolts as the high energy of sensitivity, selectivity is generally 30 decibels, and mirror image disturbs and reaches 6～10 decibels, and interference free performance is relatively poor; They are two years old, the structure heaviness, function singleness, medium wave, the general mechanical switch that adopts of shortwave conversion, inconvenient operation, reliability is relatively poor, be to design complicated as shortcoming with electronic switch, used for electronic device many, because the influence of distribution parameter, the board design difficulty was big, cost is high when particularly frequency was higher; Its three, the circuit complexity is made difficulty, the debugging operation is many and homogeneity of product that produce in batches is poor, performance index are difficult to improve, and facts have proved traditional train broadcast transmitter, the needs of incompatible especially modern electric train are then met an urgent need and are waited to improve.

The purpose of this utility model is to develop a kind of speech amplifier that is specially adapted to modern electric train, when receiving AM band, and available common single-conversion digital tuning microprocessor, the receive mode of realization double conversion; The utility model adopts the first higher IF-FRE, and design is in a wave band when receiving amplitude modulation long wave, medium wave, shortwave, and its frequency range can cover fully, and its performance can reach the standard of one-level machine of the broadcasting receiver of national regulation; Circuit reduction, simple in structure, multiple functional, reliability is high, easy production, cost are low, a kind of train broadcast transmitter that is highly suitable for producing in enormous quantities.

The utility model is realized by following steps: see accompanying

drawing

1 or 2, it comprises the rectangle cabinet, case front panel, chassis backplane, the cabinet left plate, the cabinet right plate, case backboard, recording playback circuit part, the radio reception circuit part, recording, player core is contained in the left side of case front panel, middle side, recording playback circuit plate is contained in the chassis backplane right side, the radio reception circuit board is inserted on the cabinet right plate, digital tuning microcontroller circuit plate is contained in the case front panel right side, first local oscillator is housed on the radio reception circuit board, first frequency conversion, second local oscillator, second frequency conversion and analog subtracter; It is characterized in that: the amplitude modulation that is contained on the radio reception circuit board partly adopts double conversion to receive, and receive frequency is through capacitor C ₁Be coupled to integrated circuit (IC) ₁, when receive frequency was 531kHz, because of its first local oscillator is tunable, then first local oscillator can produce the 55.531MHz frequency, and obtaining difference frequency signal after the frequency conversion is 55MHz first intermediate-freuqncy signal, and its first intermediate-freuqncy signal is through T ₁, TX ₁Deliver to the input of second frequency conversion, integrated circuit (IC) ₃The 1st pin, second local frequency is 54.550MHz, it is exported through capacitor C ₇One end and integrated circuit (IC) ₃The 3rd pin links to each other, and obtains second intermediate frequency of 450kHz difference frequency signal for this speech amplifier behind the double conversion; First local frequency and second local frequency are utilized analog subtracter, and the frequency of phase locking that obtains being scheduled to is delivered to the pll lock of digital tuning microprocessor, realize that double conversion receives.

The first local oscillator 55.531MHz frequency signal is by integrated circuit (IC) ₁The 7th foot meridian capacitor device C ₉One end is connected to integrated circuit (IC) ₂The 4th pin; The second local oscillator 54.550MHz frequency signal is by capacitor C ₈One end is connected to integrated circuit (IC) ₂The 8th pin; The difference that the first local frequency 55.531MHz deducts the second local frequency 54.550MHz is that 981kHz promptly is a frequency of phase locking, and its frequency of phase locking is by integrated circuit (IC) ₆The output of the 6th pin is delivered to digital tuning microprocessor phase-locked loop through low pass filter LFP, finishes frequency lock.

Select integrated circuit (IC) for use ₁Be the frequency mixer that comprises local oscillator, be received frequency by capacitor C ₁An end connect IC ₁The 4th pin, first local oscillator are by coil L ₁With variable capacitance diode D ₁Compose in parallel resonant tank, capacitor C ₄One end and L ₁Link to each other C ₄The other end is coupled to IC ₁The 8th pin forms first local oscillator; By integrated circuit (IC) ₁The first intermediate frequency 55MHz after the 6th pin output mixing is again by coil T ₁, crystal filter TX ₁Be sent to integrated circuit (IC) after the frequency-selecting ₃The 1st pin, by the phase-locked loop of digital tuning microprocessor, the tuning voltage VT that sends back to passes through resistor R ₁Be added to variable capacitance diode D ₁Negative terminal is with tuned frequency; Resistor R ₄One end ground connection, the other end and R ₃The series connection of one end, R ₄, R ₃The common point that links to each other and the oscillating tube TR of second local oscillator ₁Base stage link to each other, as TR ₁Biasing resistor, crystal TX ₂Two are terminated at oscillating tube TR ₁Base stage and collector electrode, capacitor C ₆One termination TR ₁Base stage, other end ground connection is crystal TX ₂Series capacitance, coil T2 resonance is second local oscillator in 54.550MHz; Integrated circuit (IC) ₃Be broadcast receiver intermediate frequency amplifier, wave detector integrated circuit commonly used, IC ₃The 1st pin is imported first intermediate frequency and is 55MHz and IC as previously mentioned ₃The second local oscillator 54.550MHz signal frequency of the 3rd pin carries out obtaining the second intermediate frequency 450KHz after the mixing, carries out intermediate frequency and amplifies and detection; Integrated circuit (IC) ₁The 7th pin is the first local oscillation signal output, C ₉One end is connected to IC ₁The 7th pin, capacitor C ₉The other end is connected to IC ₂Input the 4th pin, capacitor C ₇One end connects IC ₃The 3rd pin, C ₇The other end and C ₈One end links to each other, and this point is the output of second local oscillator, by C ₈The other end be coupled to IC ₂The 8th pin, by IC ₂Mixing is subtracted each other, at IC ₂Load resistance R on the 6th pin ₂The difference frequency of last taking-up is delivered to the digital tuning microprocessor and is carried out frequency lock behind the LFP low pass filter.Described low pass filter LFP cut-off frequency scope should be higher than the most significant end of receive frequency range.

The utility model has the advantages that: this speech amplifier has adopted double conversion at amplitude modulation radio reception wave band, the two-stage local oscillator, designed analog subtracter cleverly, it is superhet digital tuning microprocessor with existing single-conversion, realized being applicable to the receive mode of double conversion, because first IF-FRE is higher, only can finish long wave with a wave band, medium wave, the covering of each frequency of shortwave, make its circuit obtain simplifying, easy to operate, improved performance index, can reach every index request of broadcasting receiver one-level machine of national regulation such as sensitivity fully less than 5 microvolts, selectivity is greater than 40 decibels, mirror image disturbs greater than 40 decibels; Having rational in infrastructure, reliability height is that a kind of ultrathin use touched the speech amplifier that keyboard tuning multiple functional, easy production, producing cost are low, be specially adapted to modern electric train.

Accompanying drawing 1. train broadcast transmitter cabinet panel schematic diagrames: it comprises that 1 is recorder core; 2 is player core;

3 touch keyboard for the digital tuning microprocessor.

Accompanying drawing 2. train broadcast transmitter structural representations: it comprises that 1 is recording playback line parallel circuit plate; 2 are radio reception portion

The parallel circuit plate.

Accompanying drawing 3. train broadcast transmitter block diagrams: it comprises that 1 is first frequency converter; 2 is first local oscillator; 3 is

Two local oscillators; 4 is analog subtracter; 5 is low pass filter; 6 is second frequency converter; 7 are

In put wave detector; 8 are audio frequency output; 9 is digital display screen; 10 is microprocessor; 11

Be keyboard.

Accompanying drawing 4. train broadcast transmitter amplitude modulation radio reception part electrical schematic diagrams.

Embodiment of the present utility model is:

One, the amplitude modulation radio reception wave band of speech amplifier has adopted double conversion, two-stage local oscillator and analog subtracter, with existing

The superhet digital tuning microprocessor of single-conversion, be applicable to that the receive mode of double conversion is seen

Accompanying drawing 3, its circuit constitute first frequency converter 1, first local oscillator 2, second local oscillator, 3 analog subtractions

Device 4, low pass filter 5, second frequency converter 6, in put wave detector 7, audio frequency output 8, numeral

Display screen 9, microprocessor 10, keyboard 11.

Two, described integrated circuit (IC) ₁, IC ₂All adopt TA7358; IC ₃For TA8132 with guaranteed performance and index.

Three, see accompanying drawing 1, recorder core 1, player core 2, tuning microprocessor touch keyboard 3 with structure-preserving

Rationally distributed.See accompanying drawing 2, recording playback line parallel circuit plate 1, radio reception partial circuit plate 2 are to guarantee

Rational in infrastructure, dependable performance.

Four, this speech amplifier is to adopt existing 48 volts of dc battery jars power supply on the train, could guarantee operate as normal.

Claims

1. train broadcast transmitter, it comprises rectangle cabinet, case front panel, chassis backplane, cabinet left plate, cabinet right plate, case backboard, recording playback circuit part, the radio reception circuit part, recording, player core are contained in the left side of case front panel, middle side, recording playback circuit plate is contained in the chassis backplane right side, the radio reception circuit board is inserted on the cabinet right plate, digital tuning microcontroller circuit plate is contained in the case front panel right side, first local oscillator, first frequency conversion are housed, second local oscillator, second frequency conversion and analog subtracter on the radio reception circuit board; It is characterized in that: the amplitude modulation that is contained on the radio reception circuit board partly adopts double conversion to receive, and receive frequency is through capacitor C ₁Be coupled to integrated circuit (IC) ₁, when receive frequency was 531kHz, because of its first local oscillator is tunable, then first local oscillator can produce the 55.531MHz frequency, and obtaining difference frequency signal after the frequency conversion is 55MHz first intermediate-freuqncy signal, and its first intermediate-freuqncy signal is through T ₁, TX ₁Deliver to the input of second frequency conversion, integrated circuit (IC) ₃The 1st pin, second local frequency is 54.550MHz, it is exported through capacitor C ₇One end and integrated circuit (IC) ₃The 3rd pin links to each other, and obtains second intermediate frequency of 450kHz difference frequency signal for this speech amplifier behind the double conversion; First local frequency and second local frequency are utilized analog subtracter, and the frequency of phase locking that obtains being scheduled to is delivered to the pll lock of digital tuning microprocessor, realize that double conversion receives.

2. according to the described speech amplifier of claim 1, it is characterized in that: the first local oscillator 55.531MHz frequency signal is by integrated circuit (IC) ₁The 7th foot meridian capacitor device C ₉One end is connected to integrated circuit (IC) ₂The 4th pin; The second local oscillator 54.550MHz frequency signal is by capacitor C ₈One end is connected to integrated circuit (IC) ₂The 8th pin; The difference that the first local frequency 55.531MHz deducts the second local frequency 54.550MHz is that 981kHz promptly is a frequency of phase locking, and its frequency of phase locking is by integrated circuit (IC) ₆The output of the 6th pin is delivered to digital tuning microprocessor phase-locked loop through low pass filter LFP, finishes frequency lock.

3. according to claim 1 or 2 described speech amplifiers, it is characterized in that: select integrated circuit (IC) for use ₁Be the frequency mixer that comprises local oscillator, be received frequency by capacitor C ₁An end connect IC ₁The 4th pin, first local oscillator are by coil L ₁With variable capacitance diode D ₁Compose in parallel resonant tank, capacitor C ₄One end and L ₁Link to each other C ₄The other end is coupled to IC ₁The 8th pin forms first local oscillator; By integrated circuit (IC) ₁The first intermediate frequency 55MHz after the 6th pin output mixing is again by coil T ₁, crystal filter TX ₁Be sent to integrated circuit (IC) after the frequency-selecting ₃The 1st pin, by the phase-locked loop of digital tuning microprocessor, the tuning voltage VT that sends back to passes through resistor R ₁Be added to variable capacitance diode D ₁Negative terminal is with tuned frequency; Resistor R ₄One end ground connection, the other end and R ₃The series connection of one end, R ₄, R ₃The common point that links to each other and the oscillating tube TR of second local oscillator ₁Base stage link to each other, as TR ₁Biasing resistor, crystal TX ₂Two are terminated at oscillating tube TR ₁Base stage and collector electrode, capacitor C ₆One termination TR ₁Base stage, other end ground connection is crystal TX ₂Series capacitance, coil T2 resonance is second local oscillator in 54.550MHz; Integrated circuit (IC) ₃Be broadcast receiver intermediate frequency amplifier, wave detector integrated circuit commonly used, IC ₃The 1st pin is imported first intermediate frequency and is 55MHz and IC as previously mentioned ₃The second local oscillator 54.550MHz signal frequency of the 3rd pin carries out obtaining the second intermediate frequency 450KHz after the mixing, carries out intermediate frequency and amplifies and detection; Integrated circuit (IC) ₁The 7th pin is the first local oscillation signal output, C ₉One end is connected to IC ₁The 7th pin, capacitor C ₉The other end is connected to IC ₂Input the 4th pin, capacitor C ₇One end connects IC ₃The 3rd pin, C ₇The other end and C ₈One end links to each other, and this point is the output of second local oscillator, by C ₈The other end be coupled to IC ₂The 8th pin, by IC ₂Mixing is subtracted each other, at IC ₂Load resistance R on the 6th pin ₂The difference frequency of last taking-up is delivered to the digital tuning microprocessor and is carried out frequency lock behind the LFP low pass filter.Described low pass filter LFP cut-off frequency should be higher than the most significant end of receive frequency range.