CN2319961Y

CN2319961Y - Microcomputerized phaselocked FM transmitter

Info

Publication number: CN2319961Y
Application number: CN 98210312
Authority: CN
Inventors: 陈仪坤
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-01-15
Filing date: 1998-01-15
Publication date: 1999-05-19
Anticipated expiration: 2008-01-15

Abstract

The utility model discloses a microcomputer phase-locking FM transmitter which comprises an audio signal picking-up circuit, a line signal input circuit, a pre-amplifying circuit, a frequency deviation displaying circuit, an inner and an outer monitoring circuits, a remote control coding circuit, a high frequency amplifying circuit, a power amplifying circuit, a frequency displaying circuit and a power supply circuit. The utility model is characterized in that the utility model also comprises an FM modulating circuit and a microcomputer phase-locking circuit, wherein the microcomputer phase-locking circuit can ensure the good stability of the oscillating frequency of the FM modulating circuit. The utility model has the advantages of adjustable transmitting frequency, big frequency deviation and high signal-to-noise, and is especially suitable for villages and cities of the China.

Description

Microcomputer frequency modulation of the phase locking transmitter

The utility model relates to broadcasting equipment, especially relates to a kind of microcomputer frequency modulation of the phase locking transmitter.

Existing frequency modulated transmitter, though the frequency modulated transmitter that particularly is used in the FM broadcasting of rural area has the advantage that just can send signal without stringing at a distance, but there is the frequency shortcoming of drift easily, whether frequency drift easily makes frequency modulated transmitter can't be stabilized in a fixed frequency and transmits, or not when ringing when making receiver, and is intermittent, cause and normally to listen to, and the tranmitting frequency adjustability of general transmitter is relatively poor, and frequency deviation is also little, is subjected to external interference easily.

The purpose of this utility model is to provide the microcomputer frequency modulation of the phase locking transmitter that a kind of fm modulation circuit frequency of oscillation stability is good, tranmitting frequency is adjustable, frequency deviation is big.

The purpose of this utility model is achieved in that the utility model comprises the audio signal pick-up circuit, the line signal input circuit, pre-amplification circuit, inside and outside monitoring circuit, the frequency deviation display circuit, the remote control coding circuit, high-frequency amplifier circuit, power amplification circuit, frequency display circuit and power circuit, feature is that it also comprises fm modulation circuit and microcomputer phase lock circuitry, the audio signal of amplifying through pre-amplification circuit or send into fm modulation circuit from the signal that the line signal input circuit comes and carry out the frequency modulation modulation, after being amplified by high-frequency amplifier circuit again, the FM signal of ovennodulation sends into power amplification circuit and frequency display circuit respectively, the FM signal of amplifying through power amplification circuit, by transmitting antenna to aerial emission; The microcomputer phase lock circuitry compares the FM signal time-base signal inner with it that amplifies through high-frequency amplifier circuit, and output error signal feeds back to fm modulation circuit, the stable oscillation stationary vibration frequency.

The utility model locks the frequency of oscillation of fm modulation circuit owing to designed the microcomputer phase lock circuitry, thereby can guarantee that the frequency of oscillation stability is good, can reach 10 ^-6, and tranmitting frequency is adjustable, and the user can change frequency as required voluntarily, and its maximum frequency deviation can reach ± 150kHZ, so it has very high signal to noise ratio, and the receiver audibility is also fine, and the utility model is very suitable for the use in China rural area, city.

Fig. 1 is a circuit block diagram of the present utility model.

Fig. 2 is the circuit theory diagrams of fm modulation circuit, high-frequency amplifier circuit, microcomputer phase lock circuitry.

Below in conjunction with embodiment the utility model is described in further detail.

The utility model comprises audio signal pick-up circuit, line signal input circuit, pre-amplification circuit, frequency deviation display circuit, inside and outside monitoring circuit, remote control coding circuit, fm modulation circuit, high-frequency amplifier circuit, microcomputer phase lock circuitry, power amplification circuit, frequency display circuit and power circuit.

By the next audio signal of audio signal pick-up circuit, carrying out signal by pre-amplification circuit amplifies, the remote control coding circuit is also sent into its code signal pre-amplification circuit and is carried out the signal amplification, the signal that is exaggerated has two-way to deliver to frequency deviation display circuit and inside and outside monitoring circuit respectively, the signal that the Third Road signal comes with the line signal input circuit is sent into fm modulation circuit and is carried out the frequency modulation modulation, carrying out signal through the FM signal of ovennodulation by high-frequency amplifier circuit amplifies, be divided into three the tunnel again, the first via sends frequency display circuit to, the second the tunnel sends power amplification circuit to carries out power amplification, through the FM signal of power amplification by transmitting antenna to aerial emission, Third Road sends the microcomputer phase lock circuitry to, the microcomputer phase lock circuitry carries out bit comparison mutually to the FM signal that high-frequency amplifier circuit comes as the inner time-base signal of sampled signal and its, output error signal feeds back to fm modulation circuit, the stable oscillation stationary vibration frequency.Power circuit provides required voltage for other circuit.

Fm modulation circuit is by two variable capacitance diode D ₁, D ₂, resistance R ₅-R ₇Capacitor C ₃-C ₇, inductance L ₁-L ₄, field effect transistor T ₄Form, wherein inductance L ₁One termination polar capacitor C ₂Positive pole, two variable capacitance diode D of another termination ₁, D ₂The common port of negative electrode, variable capacitance diode D ₁Plus earth, variable capacitance diode D ₂Anode connect inductance L ₂, capacitor C ₃The common port of each end, inductance L ₂Other end ground connection, capacitor C ₃Another termination field effect transistor T ₄Grid, field effect transistor T ₄Source electrode and resistance R ₆, inductance L ₄Ground connection after connecting successively, capacitor C ₄Be attempted by field effect transistor T ₄Grid and source electrode between, resistance R ₅Be attempted by field effect transistor T ₄Grid and ground between, capacitor C ₆Be attempted by field effect transistor T ₄Source electrode and ground between, capacitor C ₅Be attempted by field effect transistor T ₄Drain electrode and ground between, inductance L ₃One termination field effect transistor T ₄Drain electrode, another termination polar capacitor C ₇Positive pole, polar capacitor C ₇Minus earth, resistance R ₇One termination polar capacitor C ₇Positive pole, the other end and inductance L ₅, resistance R ₈Connect after the series connection+12V voltage.

High-frequency amplifier circuit is by field effect transistor T ₅, triode T ₆, T ₇, capacitor C ₉-C ₁₁And other element is formed.

The microcomputer phase lock circuitry is by phase-locked integrated circuit (IC), resistance R ₁, R ₂, inductance L ₆, diode D ₃～D ₉, push-button switch AN ₁, AN ₂And other element composition, wherein sampled signal input 36 pin and capacitor C of phase-locked integrated circuit (IC) ₉Meet triode T after the series connection ₆Collector electrode, error signal output 33 pin and resistance R ₁Meet triode T after the series connection ₂Base stage, triode T ₂Emitter meet triode T ₁Base stage, triode T ₁Grounded emitter, triode T ₁, T ₂Collector electrode all meet field effect transistor T ₃Grid, field effect transistor T ₃Source electrode and resistance R ₂Meet polar capacitor C after the series connection ₂Positive pole and inductance L ₁The common port of one end, field effect transistor T ₃Drain electrode and inductance L ₆, L ₅, resistance R ₈Connect after the series connection+12V voltage, crystal oscillator JZ is connected in parallel on the vibration of phase-locked integrated circuit (IC) and holds between 40 pin, 41 pin diode D ₉The negative electrode downward search that connects phase-locked integrated circuit (IC) hold 44 pin, anode and button switch AN ₁Series connection back ground connection, diode D ₇Negative electrode meet upwards search end 2 pin, anode and push-button switch AN ₂Series connection back ground connection.Diode D ₃～D ₉The network of forming can directly change the frequency division index of the inner variable frequency divider of phase-locked integrated circuit (IC), thereby changes frequency of oscillation.Push-button switch AN ₁Be downward search key, push-button switch AN ₂Be the search key that makes progress, triode T ₁, T ₂Form active filter, field effect transistor T ₃Be constant-current source.

By pre-amplification circuit and the next signal process resistance R of line signal input circuit ₄, resistance R ₃And capacitor C ₁The preemphasis circuit that composes in parallel, coupling capacitance C ₂, inductance L ₁Transfer to fm modulation circuit, be added in variable capacitance diode D ₁, D ₂On, the FM signal that the process fm modulation circuit is modulated is from field effect transistor T ₄Source electrode output, through coupling capacitance C ₈Be sent to the field effect transistor T in the high-frequency amplifier circuit ₅Grid, FM signal is again by field effect transistor T ₅, triode T ₆After the amplification, the one tunnel through coupling capacitance C ₁₀Add to triode T ₇Base stage, again by triode T ₇Send frequency display circuit and power amplification circuit respectively to, another road is through coupling capacitance C ₉Sampled signal input 36 pin that are sent to phase-locked integrated circuit (IC) are as sampled signal, behind the variable frequency divider frequency division of this sampled signal through phase-locked integrated circuit (IC) inside, the time-base signal that produces with crystal oscillator JZ carries out bit comparison mutually, the error signal that obtains is from the output of error signal output 33 pin, through three utmost point T ₁, T ₂, field effect transistor T ₃Acting in conjunction, convert error signal to direct voltage, pass through resistance R ₂, inductance L ₁Add to variable capacitance diode D ₁, D ₂On, the frequency of oscillation of change fm modulation circuit.When frequency of oscillation was unstable, error signal output 33 pin will output error signal, by feedback regulation, frequency of oscillation is tended towards stability, and error voltage trends towards zero.By capacitor C ₂The signal that comes is used for changing the instantaneous frequency of oscillator, by resistance R ₂The signal that comes is used for changing the centre frequency of oscillator.

Claims

1, a kind of microcomputer frequency modulation of the phase locking transmitter, comprise audio signal pick-up circuit, line signal input circuit, pre-amplification circuit, frequency deviation display circuit, inside and outside monitoring circuit, remote control coding circuit, high-frequency amplifier circuit, power amplification circuit, frequency display circuit and power circuit, it is characterized in that: it also comprises frequency modulation system circuit and microcomputer phase lock circuitry, and fm modulation circuit is by two variable capacitance diode (D ₁), (D ₂), resistance (R ₅-R ₇), electric capacity (C ₃-C ₇), inductance (L ₁-L ₄), efficient pipe (T ₄) composition, wherein inductance (L ₁) a termination polar capacitor (C ₂) positive pole, two variable capacitance diode (D of another termination ₁), (D ₂) the common port of negative electrode, variable capacitance diode (D ₁) plus earth, variable capacitance diode (D ₂) anode meet inductance (L ₂), electric capacity (C ₃) common port of each end, inductance (L ₂) other end ground connection, electric capacity (C ₃) another termination field effect transistor (T ₄) grid, field effect transistor (T ₄) source electrode and resistance (R ₆), inductance (L ₄) the back ground connection of connecting successively, electric capacity (C ₄) be attempted by field effect transistor (T ₄) grid and source electrode between, resistance (R ₅) be attempted by field effect transistor (T ₄) grid and ground between, electric capacity (C ₆) be attempted by field effect transistor (T ₄) source electrode and ground between, electric capacity (C ₅) be attempted by field effect transistor (T ₄) drain electrode and ground between, inductance (L ₃) a termination field effect transistor (T ₄) drain electrode, another termination polar capacitor (C ₇) positive pole, polar capacitor (C ₇) minus earth, resistance (R ₇) a termination polar capacitor (C ₇) positive pole, the other end and inductance (L ₅), resistance (R ₈) connect+12V voltage after the series connection; Phase-locked integrated circuit (IC) sampled signal input (36) pin and electric capacity (C in the microcomputer phase lock circuitry ₉) meet triode (T after the series connection ₆) collector electrode, error signal output (33) pin and resistance (R ₁) meet triode (T after the series connection ₂) base stage, triode (T ₂) emitter meet triode (T ₁) base stage, triode (T ₁) grounded emitter, triode (T ₁), (T ₂) collector electrode all meet field effect transistor (T ₃) grid, field effect transistor (T ₃) source plate and resistance (R ₂) meet polar capacitor (C after the series connection ₂) positive pole and inductance (L ₁) common port of an end, field effect transistor (T ₃) drain electrode and inductance (L ₆), (L ₅), resistance (R ₈) connect+12V voltage after the series connection, crystal oscillator (JZ) is connected in parallel between vibration end (40) pin, (41) pin of phase-locked integrated circuit (IC), diode (D ₉) negative electrode connect downward search end (44) pin of phase-locked integrated circuit (IC), anode and button switch (AN ₁) series connection back ground connection, diode (D ₇) negative electrode meet upwards search end (2) pin, anode and push-button switch (AN ₂) series connection back ground connection.