The single-ended input finger signal has a reference end and a signal end. The reference end is generally ground. The difference is to differentially transform the single-ended signal and output two signals, one in phase with the original signal and one inverted from the original signal. Differential signals have strong anti-common-mode interference capability and are suitable for long-distance transmission. Single-ended signals do not have this function. After the signal is transmitted to the receiving end, the differential signal can be converted into a single-ended signal. In many cases, a single-ended signal needs to be converted to a differential signal. This requires a circuit that converts a single-ended signal into a differential signal, a single-ended-differential converter.
Single-ended to differential signal circuit
The circuit in the above figure is a dual amplifier feedback structure in which the op amp determines the accuracy and noise performance of the circuit, while the differential amplifier acts as a single-ended-differential conversion. This feedback structure rejects the AD8476's error, including noise, distortion, offset, and drift, which replaces the op amp feedback loop inside the AD8476 with the large open-loop gain of the op amp. Essentially, this structure uses the open-loop gain of the op amp for the input, attenuating the error of the AD8476.
The external resistors RF and RG in the figure set the gain of the single-ended-differential amplifier, ie
Short-circuit RF, RG open, can be set to the lowest gain of 2.
As with any feedback connection, great care must be taken to ensure system stability. The cascading of the OP1177 and the AD8476 forms a combined differential output op amp with an open-loop gain that is the product of the OP1177 open-loop gain and the AD8476 closed-loop gain. Therefore, the closed-loop bandwidth of the AD8476 adds one pole to the open-loop gain of the OP1177. To ensure stability, the bandwidth of the AD8476 should be higher than the unity gain frequency of the OP1177. When the closed-loop gain of the circuit is greater than 2, this requirement can be relaxed because the resistance feedback
The network effectively reduces the unity gain frequency of the OP1177 by RG/(RG+RF). The bandwidth of the AD8476 is 5MHz, and the unity gain frequency of the OP1177 is 1MHz, so the circuit will not have stability problems at any gain.
When using an op amp with a unity gain frequency much larger than the differential amplifier bandwidth, a bandwidth limiting capacitor CF can be inserted as shown. Capacitor CF and feedback resistor RF form an integrator, and the bandwidth of the whole circuit is:
The reason for the bandwidth equation 1/2 factor is that the output of the circuit is based on single-ended feedback, not differential. Therefore, the feedback coefficient and bandwidth of the circuit are halved.
If this reduced bandwidth is less than the closed loop bandwidth of the differential amplifier, the circuit will be stable. This bandwidth limiting technique can also open the RG to get a gain of 2.
Yuhai company develop and produce of various rings sizes, bearing variety of electrode and metallisation configurations. This variety of Rings is fabricated from various material formulations for applications such as high power, sensitivity, stability.
Features
· • electrode type on request
· • Surface roughness on request, for specific demanding application
· • Thickness/Radial frequency tuning available on request
• Wide choice of PZT formulations
Applications include
• Sensors
• Welding
• Ultrasonic cleaning
• Precise Measurement
• Ultrasonic scalpel
• Cauterisation
• Phacoemulsification
• Therapeutic ultrasound
• Accelerometers
Dimension range
|
Outer diameter |
3-180mm |
|
Inner diameter |
1-150mm |
|
Thickness |
0.2-25mm |
Piezo Ring,Pzt Ring,Piezoelectric Ceramic Ring,Piezo Ceramic Ring
Zibo Yuhai Electronic Ceramic Co., Ltd. , https://www.yhpiezo.com