CN205051663U - Step -by -step attenuating device - Google Patents

Abstract

The utility model discloses a step attenuation device, which comprises a signal input terminal and a signal output terminal. The signal input terminal receives an external modulation wave whose center frequency is X, and comprises a subtraction mixer, whose input terminal is connected to the signal input terminal. terminal, for outputting a first band whose center frequency is A; the attenuator, whose input terminal is connected to the output terminal of the subtractive mixer, for attenuating the first band; the compensation mixer, whose input terminal is connected to The output terminal of the attenuator is connected to the signal output terminal and outputs the second band whose center frequency is X. Perform amplitude attenuation. At this time, the center frequency of the attenuated band is smaller than the first band. When it passes through the compensation mixer, the attenuated band can be output again, and its envelope curve will not be changed at this time. But its envelope curve has changed (attenuation), and the compensation mixer can change its center frequency to the original input center frequency, so as to ensure that its output waveform remains unchanged.

Description

step attenuation device

technical field

The utility model relates to a signal attenuation device, in particular to a step attenuation device.

Background technique

An attenuator is an electronic component that provides attenuation and is widely used in electronic equipment. Its main purpose is: (1) Adjust the size of the signal in the circuit; (2) In the comparison method measurement circuit, it can be used for direct reading The attenuation value of the network under test; (3) Improving impedance matching. If some circuits require a relatively stable load impedance, an attenuator can be inserted between this circuit and the actual load impedance to buffer impedance changes. But in the use of signal transmission, when the signal passes through the attenuator, the center frequency of its band will be changed. For example, when the signal band input of 2GHZ passes through the attenuator, the value of the center frequency will float. In this way, it is difficult to guarantee its output. Signals can be received and processed.

Utility model content

Aiming at the deficiencies in the prior art, the purpose of this utility model is to provide a compensation mixer for frequency mixing compensation, so that the output frequency can be guaranteed to be stable.

In order to achieve the above object, the utility model provides the following technical solutions: a step attenuation device, including a signal input terminal and a signal output terminal, the signal input terminal receives an external modulation wave whose center frequency is X, including subtractive mixing A device, whose input terminal is connected to the signal input terminal, is used to output a first band whose center frequency is A; an attenuator, whose input terminal is connected to the output terminal of the subtractive mixer, and is used to attenuate the first band; The input terminal of the mixer is connected to the output terminal of the attenuator, and the output terminal is connected to the signal output terminal to output the second band whose center frequency is X.

With this setting, when the external input signal enters the step attenuation device, its center frequency will be shifted down through the subtractive mixer first, and become a first band with a center frequency of A, which is used to modulate the first band The local oscillator source can be any adjustable oscillatory wave. At this time, its envelope curve will not change. When it enters the attenuator, the amplitude will be attenuated. At this time, the center frequency of the attenuated band is smaller than the first band. When When it passes through the compensation mixer, the attenuated band can be output again, and its envelope curve will not be changed at this time, but its envelope curve has changed (attenuated), and the compensation mixer can change its center The frequency becomes the center frequency of the original input, which can ensure that the output waveform remains unchanged.

The utility model can be further set as: the attenuator is a step attenuator.

The step attenuator consists of 3 or 4 cascaded sections with special attenuation values such as 1, 2, 4, 10, 20 and 40dB. Both series provide the choice, performance and precision expected from Agilent attenuators and reliability; 11, 70 or 90dB attenuation range, 1dB and 10dB step size, 4 million cycles per part, repeatability better than 0.03dB, a variety of connector sizes to choose from, and can also Available with female or male connectors. RF connector options include 26.5GHz K-type precision 3.5mm or 2.92mm connectors and L-type precision 3.5mm or 2.92mm connectors, while the 2.92mm connector form is compatible with both 3.5mm and SMA connectors. HP recommends using stronger 2.4mm and 3.5mm connectors, and you can set the attenuation value of the component attenuator according to your needs to ensure its attenuation frequency.

The utility model can be further configured as: the local oscillation signals of the subtraction mixer and the compensation mixer are generated by a direct digital synthesizer.

DDS, like DSP (Digital Signal Processing), is also a key digital technology. DDS is the English abbreviation of Direct Digital Synthesizer (DirectDigitalSynthesizer). DDS is a new frequency synthesis technology that directly synthesizes the required waveform from the concept of phase. Compared with traditional frequency synthesizers, DDS has the advantages of low cost, low power consumption, high resolution and fast conversion time. It is widely used in the field of telecommunications and electronic instruments, and is a key technology to realize the full digitalization of equipment. A high-precision local oscillator signal can be modulated by DDS to ensure the band precision of its output.

The utility model can be further set as: a first frequency multiplier is coupled between the subtraction mixer and the direct digital synthesizer; a second frequency multiplier is coupled between the compensation mixer and the direct digital synthesizer device. Through the setting of two frequency multipliers, the signal of the local oscillator source can be amplified according to the requirement, so that the utility model can adapt to more input and output requirements.

By adopting the above technical scheme, the following beneficial effects are achieved: when the external input signal enters the step attenuation device, its center frequency is moved downward through the subtractive mixer, and becomes a first band whose center frequency is A. The local oscillator source used to modulate the first band can be any adjustable oscillator wave. At this time, its envelope curve will not change. When it enters the attenuator, the amplitude will be attenuated. At this time, the attenuated band's The center frequency is smaller than the first band. When it passes through the compensation mixer, the attenuated band can be output again. At this time, its envelope curve will not be changed, but its envelope curve has changed (attenuated). The compensation mixer can change its center frequency to the original input center frequency, so as to ensure that the output waveform remains unchanged.

Description of drawings

Fig. 1 is the connection schematic diagram of the utility model.

Reference signs: 1. Signal input terminal; 2. Subtraction mixer; 21. First frequency multiplier; 3. Step attenuator; 4. Compensation mixer; 41. Second frequency multiplier; 5. Signal Output terminal; 6. Digital direct synthesizer.

detailed description

The utility model embodiment is further described with reference to Fig. 1.

A step attenuation device, including a signal input terminal 1 and a signal output terminal 5, the signal input terminal 1 receives an external modulation wave whose center frequency is X, and includes a subtractive mixer 2, whose input terminal is connected to the signal input terminal 1, for outputting a first band whose center frequency is A; the attenuator, whose input is connected to the output of the subtractive mixer 2, is used to attenuate the first band; the compensation mixer 4, whose input Connected to the output terminal of the attenuator, its output terminal is connected to the signal output terminal 5 and outputs the second band whose center frequency is X, for example, the input frequency band is 2GHz, then when passing through the subtractive mixer 2, due to the first multiplication The frequency converter 21 and the digital direct synthesizer 6 output a local oscillator source with a center frequency of 2.07GHz to the subtractive mixer 2, so that the output band is 70MHz, which can satisfy the normal frequency response of the step attenuator 3. After the attenuator attenuates Perform center frequency compensation amplification to amplify the center frequency to the attenuated output frequency of 2GHz. The frequency mixing circuit used by the subtraction mixer 2 is the most common frequency mixing circuit, and will not be repeated here.

With this setting, when the external input signal enters the step attenuation device, its center frequency will be shifted down through the subtraction mixer 2 first, and become a first band with a center frequency of A, which is used to modulate the first The local oscillation source of the band can be any adjustable oscillatory wave. At this time, its envelope curve will not change. When it enters the attenuator, the amplitude will be attenuated. At this time, the center frequency of the attenuated band is smaller than that of the first band. When it passes through the compensation mixer 4, the attenuated band can be output again, and its envelope curve will not be changed at this time, but its envelope curve has changed (attenuation), and the compensation mixer 4 can Change its center frequency to the original input center frequency, so as to ensure that the output waveform remains unchanged.

The attenuator is a step attenuator 3 . The Step Attenuator 3 consists of 3 or 4 cascaded sections with special attenuation values such as 1, 2, 4, 10, 20 and 40dB. Both series provide the choice, performance, Accuracy and reliability; 11, 70 or 90dB attenuation range, 1dB and 10dB step size, 4 million cycles per part, repeatability better than 0.03dB, a variety of connector sizes to choose from, and Available with female or male connectors. RF connector options include 26.5GHz K-type precision 3.5mm or 2.92mm connectors and L-type precision 3.5mm or 2.92mm connectors, while the 2.92mm connector form is compatible with both 3.5mm and SMA connectors. HP recommends using stronger 2.4mm and 3.5mm connectors, and you can set the attenuation value of the component attenuator according to your needs to ensure its attenuation frequency.

The local oscillation signals of the subtractive mixer 2 and the compensation mixer 4 are generated by a direct digital synthesizer 6 . DDS, like DSP (Digital Signal Processing), is also a key digital technology. DDS is the English abbreviation of Direct Digital Synthesizer (DirectDigitalSynthesizer). DDS is a new frequency synthesis technology that directly synthesizes the required waveform from the concept of phase. Compared with traditional frequency synthesizers, DDS has the advantages of low cost, low power consumption, high resolution and fast conversion time. It is widely used in the field of telecommunications and electronic instruments, and is a key technology to realize the full digitalization of equipment. A high-precision local oscillation signal can be modulated through DDS to ensure the accuracy of the output band. Outputting a modulated oscillation wave through DDS is a common method well known to those skilled in the art, and will not be repeated here.

A first frequency multiplier 21 is coupled between the subtractive mixer 2 and the direct digital synthesizer 6 ; a second frequency multiplier 41 is coupled between the compensation mixer 4 and the direct digital synthesizer 6 . Through the setting of two frequency multipliers, the signal of the local oscillator source can be amplified according to the requirement, so that the utility model can adapt to more input and output requirements.

The above descriptions are only preferred implementations of the present utility model, and the protection scope of the present utility model is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present utility model all belong to the protection scope of the present utility model. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the utility model should also be regarded as the protection scope of the utility model.

Claims (4)

1. a step attenuation device, comprises signal input part and a signal output part, and described signal input part receiving center frequency is the external modulation ripple of X, it is characterized in that: comprise

Subtraction frequency mixer, its input is connected to signal input part, for exporting the first band that a centre frequency is A;

Attenuator, its input is connected to the output of subtraction frequency mixer, for decaying to first band;

Compensate frequency mixer, its input is connected to the output of attenuator, and its output is connected to signal output part and output center frequency is the second band of X.

2. a kind of step attenuation device as claimed in claim 1, is characterized in that: described attenuator is step attenuator.

3. a kind of step attenuation device as claimed in claim 1 or 2, is characterized in that: the local oscillated signal of described subtraction frequency mixer and described compensation frequency mixer is produced by digital direct synthesizer.

4. a kind of step attenuation device as claimed in claim 1 or 2, is characterized in that: be coupled with the first frequency multiplier between described subtraction frequency mixer and digital direct synthesizer; The second frequency multiplier is coupled with between described compensation frequency mixer and digital direct synthesizer.