CN2173482Y - Zero energy cross point modulator - Google Patents

Abstract

The utility model discloses a zero energy cross point modulator comprising an oscillator with adjustable frequency output and a modulator which can cause the frequency output to be adjusted to a frequency value relative to the binary bit of the input data. The oscillator and the modulator comprise a transistor, an inductor, a capacitor, and a voltage control oscillator which is composed of a capacitance with adjustable voltage and a diode. The output oscillating frequency is the modulated frequency of the modulating data. The utility model is used for the synchronic network of the radio-frequency signal in zero energy cross point. The synchronous network comprises a storing device. The storing device is used for storing data binary bit and adding the stored binary bit to the modulator so that the condition of the oscillator can be changed when the radio-frequency signal is in zero energy cross point.

Description

Zero energy cross point modulator

The utility model generally speaking relates to rf modulations, more particularly, relates to a kind of digital information modulated radio signal of using, thereby can improve the device of message transmission rate on narrow bandwidth channel.

The telegraph apparatus that employing can be transmitted given medium (no matter being lead, free space or optical fiber) always is the thing that everybody was concerned about.This problem is outstanding especially in the transmission of free space, because under the situation of wired and fiber device, can set up circuit in case of necessity.

But increase information transmitted, the general practice be with information distribution in various frequency band (being called channel).For example, the 2nd television channel adopts the frequency between 54 and 60 megahertzes, and the 3rd channel adopts the frequency between 60 and 66 megahertzes.Channel frequency, channel bandwidth, field intensity and other parameter are all regulated by certain control method.

Although come assignment information to obtain very big achievement with channel, the users that transmit information need use the channel of narrow bandwidth.

The roughly bandwidth that produces or receive the required usefulness of FM signal is:

Bandwidth B n=2(Fm+Fd) (1.10)

Wherein, Fm=modulating frequency

The Fd=frequency modulation

(under the frequency modulation situation)

Narrow bandwidth channel can be used for Speech Communication, because relevant frequency is between 300 hertz to 3,500 hertz, is in the scope of narrow bandwidth.Yet, in high-speed digital data (500,000 pulse/sec (KPS) or higher) transmission, need have wideer channel width (referring to 1.10 formulas) than general distribution.

Why need channel width to be because due to the upper and lower sideband that is produced during signal modulated RF carrier wave.Modulation is the process that information is encoded on radio-frequency carrier, its desirable various ways, and wherein the most frequently used is amplitude modulation, phase modulation and frequency modulation.The influence of these sidebands must be limited on the specified channel, in order to avoid disturb other channel.Why produce sideband and be since modulation signal optionally is added on the crest of radio-frequency carrier and the trough and remove from this crest and trough due to.If modulation signal and radio-frequency carrier synchronously so that modulation signal in place, the zero energy crosspoint beginning of radio-frequency carrier with finish, then significantly reduce or eliminated the sideband that is produced locate because cross the zero energy crosspoint, do not produce the radio-frequency (RF) energy of sideband.This zero energy crosspoint is equivalent to the time average of radio-frequency carrier signal.

Thereby the purpose of this utility model provides a kind of device that can carry out high-speed digital communication with the modulates digital data radiofrequency signal under the situation that channel width reduces.

Above-mentioned and other purpose by at a high speed on than narrow bandwidth channel transmission of digital data realize, understand these purposes from following to knowing the all-side introduction of the present utility model.

A kind of zero energy crosspoint modulator is characterized in that comprising:

Oscillator with adjustable frequency output;

In order to described frequency output is adjusted to the modulator of the frequency values relevant with importing the data binary digit;

Described oscillator and modulator comprise the voltage controlled oscillator that transistor, inductance, capacitor and voltage tunable capacitor diode are formed, and the frequency of oscillation of being exported is the frequency that modulating data is modulated;

A network synchronous when being in its zero energy crosspoint in radiofrequency signal; And

One in order to store described data binary digit and the binary digit of described storage be added to described modulating device so that change the storage device of oscillator situation when radiofrequency signal is in its zero energy crosspoint;

Described synchronizing network and storage device comprise trigger, resistor, capacitor, bias resistor, load resistor and a transistor with clock input " D ".

The utility model has following advantage:

A. in existing narrow bandwidth channel, can the transmitting high speed numerical data, and need not to change existing channel,

B. in deciding the channel scope, a plurality of high-speed digital data channels can be set, as at channel scope 48 to 50 megacycles, prior art is established one one megacycle digital data channel only, if utilize the utility model, 40 channels can be set,

C. utilize the utility model can improve the radio-frequency (RF) energy effect, because energy need not spend on the sideband radio frequency,

D. utilize the utility model numerical data more clearly on receiving, because each numerical data all can be handed over justice point beginning or ending at zero of radio frequency,

E. reduce design and installation cost because need not to add the sideband radio-frequency filter.

Describe most preferred embodiment of the present utility model with reference to the accompanying drawings in detail.

Fig. 1 is the block diagram that has the transmitter of zero energy of the present utility model crosspoint modulator.

Fig. 2 shows the practical structures of the utility model modulator.

Fig. 3 shows each waveform on the each point that appears at Fig. 2.

Fig. 4 is the frequency spectrum of the signal that sent of expression.

Fig. 1 and Fig. 2 show most preferred embodiment of the present utility model with the form of block diagram and schematic diagram respectively.Principle of the present utility model also can be applicable to frequency shift keying (FSK), pulse-code modulation (PCM), pulse-position modulation (PPM), pulse-ampli tude modulation (PFM), amplitude shift keying (ASK) and phase-shift keying (PSK).

Referring to Fig. 1.The device of most preferred embodiment comprises: modulator/oscillator, radio frequency amplifier, radio-frequency (RF) phse regulating circuit, radio frequency/data sync circuit and transmitter.This device modulates digital data radiofrequency signal that is added to data flow.Modulation is only undertaken during by the zero energy crosspoint at signal.This zero energy crosspoint is corresponding to the time average of radiofrequency signal.Modulated radiofrequency signal is gone out from antenna transmission through transmitter as the radiofrequency signal that is sent.

As shown in Fig. 1 and Fig. 2, the radiofrequency signal that is sent produces in modulator/oscillator, and the output of modulator/oscillator is added on the radio frequency amplifier.Fig. 3 (a) shows typical output waveform.As will illustrating after a while, the output frequency that draws among Fig. 3 (a) changes with the modulation signal that is added to modulating data.

As shown in Figure 2, modulator/oscillator comprises tuning circuit, the bias resistor (R3 that transistor (Q1), inductance (L1) and electric capacity (C1) are formed, R4), feedback condenser (C2), resistor (R1, R2, R5, R7, R9) with voltage tunable capacitor diode (D1), these elements form voltage controlled oscillator together.The frequency of oscillator not only depends on above-mentioned each element, also depends on voltage tunable capacitor diode (voltage variable capacitance diode) (D1).The electric capacity that voltage is adjustable, its characteristics are that its electric capacity changes with the level of adding reverse voltage.In the case, it changes L/C electric capacity according to modulation signal.Therefore the frequency of oscillation that draws is the frequency with the modulating data modulation.

As shown in Fig. 1 and Fig. 2, radio frequency amplifier is in order to drive transmitter or frequency multiplier to desired tranmitting frequency.The output of oscillator is connected with amplifier transistor Q3 through capacitor C6.(L2 C7) may be tuned to the tranmitting frequency that requires of first-harmonic or each harmonic wave of oscillator to transistor (Q3) through the L/C tuning circuit.The radio-frequency (RF) transistors amplifier plays buffer between oscillator and transmitter; When wanting to improve tranmitting frequency, this amplifier arrives higher harmonic frequency with the fundamental oscillation frequency multiplication.

Can see the most clearly from Fig. 1, as mentioned above, the output of radio frequency amplifier Q3 is added on the transmitter.Fig. 2 shows the transmitter of most preferred embodiment.The output of radio frequency amplifier is coupled through capacitor C8 and power transistor Q4.The final tuning circuit L3 of transmitter and C9 be tuned to final tranmitting frequency.The tuning circuit of transmitter has a secondary winding that radiofrequency signal is coupled on the antenna.Biasing element and filter element are assisted transmitter work.Fig. 4 shows the typical radio-frequency signal of being launched, sideband has been suppressed with frequency domain.

According to principle of the present utility model, the important point is that modulation signal is in place, the zero energy crosspoint beginning of radio driver output and finishes.This significantly reduces or has eliminated each sideband that is produced in the radiofrequency signal.Among Fig. 4, (f(c)-f(m)) and (f(c)+f(m)) show these sidebands, wherein f(c) be carrier frequency, f(m) be modulating frequency.Because the modulating clock pulse is directly directly to extract from radio frequency amplifier Q2, it just in time appears at its zero energy crosspoint extremely ideally.Yet having the time-delay phenomenon on propagating need be compensated.The radio-frequency (RF) phse regulating circuit provides this adjusting, thereby modulated process can be regulated to such an extent that make it export clock pulse (clock out) when radio frequency zero energy crosspoint.Radio frequency regulating circuit shown in Figure 2 comprises variable resistance (VR1), R8, C5 and amplifier transistor Q2.Variable resistance VR1 is connected with tuning circuit with resistor R 8, this means that the radio-frequency (RF) phse that passes through has changed 180 °.The tapping point of variable resistance is chosen suitable radio-frequency (RF) phse angle.Amplifier transistor Q2 is amplified the radiofrequency signal of correct phase, to drive " D " trigger that synchronization is used.

As shown in Figure 2, synchronous circuit is made up of with the modulating data that is input to trigger D input " D " trigger U1.Radio frequency from transistor Q2 is exported the clock pulse input terminal that is directly connected to trigger, and modulating data then is connected to the D input of trigger.When the clock threshold value of trigger is passed through in the rising of radio frequency clock pulse signal, the data binary digit is appeared at receive on the Q output of modulation circuit.Because the operating rate of trigger is limited, thereby the data binary digit is not to be added to immediately on the modulation circuit.By regulating radio-frequency (RF) phse regulating circuit (VR1), occur synchronously in the time of can making modulation binary digit and radio frequency amplifier output zero energy crosspoint.

That is launched can be with the in addition demodulation of the FM demodulator of a series of prior aries by the radiofrequency signal of principle of the present utility model modulation.The demodulator that is suitable for has the Foster-Seeley demodulator, and (Electronic Designers ' has introduction in Handbook) to this demodulator at " Electronics Engineer's design manual ".

Can know that from the above the utility model provides a kind of and uses the modulates digital data radiofrequency signal, thus the device that modulated process is only just carried out at the place, zero energy crosspoint of the radiofrequency signal that is sent basically.Though be appreciated that the block diagram of the most preferred embodiment of having listed the utility model work here and detailed element level diagram in addition, under the prerequisite that does not break away from spirit of the present utility model or scope, can carry out various modifications.

Claims (4)

1, a kind of zero energy crosspoint modulator is characterized in that comprising:

Oscillator with adjustable frequency output;

In order to described frequency output is adjusted to the modulator of the frequency values relevant with importing the data binary digit;

Described oscillator and modulator comprise the voltage controlled oscillator that transistor (Q1), inductance (L1), capacitor (C1, C2) and voltage tunable capacitor diode (D1) are formed, and the frequency of oscillation of being exported is the frequency that modulating data is modulated;

A network synchronous when being in its zero energy crosspoint in radiofrequency signal;

Described synchronizing network comprises one in order to store described data binary digit and the binary digit of described storage is added to described modulating device so that change the storage device of oscillator situation when radiofrequency signal is in its zero energy crosspoint; This storage device comprises " D " trigger with input end of clock;

Described synchronizing network also comprises resistor (R7, R9), capacitor (C5), bias resistor (R1, R2) and voltage tunable capacitor diode (D1).

2, according to the modulator of claim 1, it is characterized in that, also comprise a radio frequency amplifier of being formed by transistor (Q3), bias resistor (R12), capacitor (C6), resonant circuit (L2, C7).

3,, it is characterized in that comprising a radio-frequency (RF) phse regulating circuit, with at radio frequency zero energy crosspoint clock signal in order to modulation is regulated according to the modulator of claim 1.

4, according to each modulator of claim 1 to 3, it is characterized in that also comprising a transmitter that effectively is connected with described radio frequency amplifier, and the antenna of a signal that is obtained from the output of described transmitter in order to emission, described antenna and described transmitter are coupled effectively.

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