Circuit to aid tuning of Class-E amplifier

Cantrell, W.H.

doi:10.1109/mwsym.2000.863299

Cited by 5 publications

(5 citation statements)

References 6 publications

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“…R 5 and R L in Fig. 5(a) form a potential divider so that: Figure 5(b) uses feedback via G 5 to produce: (23) and (24) can be equated to derive G 5 as: Although it is desirable to reduce the value of R 6 as much as possible to increase efficiency, excessive gain of G 5 could lead to instability [13].…”

Section: Synthetic Impedancementioning

confidence: 99%

High linearity lead-lag style envelope modulator for RF power amplifiers

Watkins

Mimis

2015

Int. J. Microw. Wireless Technol.

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A new split frequency envelope modulator for envelope tracking radio-frequency power amplifiers is proposed based on a lead-lag network. By mathematically deriving the transfer functions of the lead-lag modulator and the conventional split frequency type, the lead-lag is shown to have a significantly flatter phase response. The frequency response of the two modulators is verified by simulation, where the phase transient of the lead-lag is significantly less than the 360° of the conventional type. They are further simulated with a 3 MHz bandwidth 3GPP long-term evolution (LTE) signal and the lead-lag shown to reduce the modulator's normalized root-mean-square error (NRMSE) from −27.3 to −39.2 dB. A practical demonstrator was developed around an existing high-efficiency modulator architecture. To maintain system efficiency synthetic impedance was incorporated in the low-frequency switched mode power supply (SMPS) path. This was achieved with voltage and current feedback around the SMPS. The dynamic wideband signal response was investigated by applying a 3 MHz LTE envelope signal to the modulator and comparing the input and output signals. The measured NRMSE was improved from −27.5 to −30.0 dB by adopting the lead-lag structure and the dynamic frequency response verifies correct operation.

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Section: Synthetic Impedancementioning

confidence: 99%

High linearity lead-lag style envelope modulator for RF power amplifiers

Watkins

Mimis

2015

Int. J. Microw. Wireless Technol.

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“…1 b produces

V_{normalout} = G_{1} \frac{R_{normalL}}{R_{normalL} + R_{2} \cdot false(G_{1} \cdot G_{2} + 1 false)} \cdot V_{in}

Comparing Figs. 1 a and b , a relationship for G 2 can be derived as

G_{2} = \frac{R_{1} - R_{2}}{R_{2} \cdot G_{1}}

As a compromise between efficiency and stability, R 2 is selected as 10% of R 1 , and reducing R 2 further can result in instability [3]. Low‐power ADSL line drivers based on Fig.…”

Section: Synthetic Impedance Amplifiermentioning

confidence: 99%

“…As a compromise between efficiency and stability, R 2 is selected as 10% of R 1 , and reducing R 2 further can result in instability [3]. Low-power ADSL line drivers based on Fig.…”

mentioning

confidence: 99%

Broadband high‐power line driver with synthetic output impedance

Watkins

Mimis

2015

Electron. lett.

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Broadband line drivers usually include a back termination resistor at the output to match to the cable they are driving. Half the output power is dissipated in this resistor, therefore halving their efficiency. The resistive termination can be replaced with synthetic impedance using a combination of voltage and current feedback. This implementation is based around a current mirror amplifier capable of producing a 40 V peak-to-peak signal into a 50 Ω load impedance from a ±24 V supply. Using bandwidth enhancement, the small signal bandwidth was 15 MHz and the full power bandwidth was 6 MHz. When driving a 50 m long terminated 50 Ω coaxial cable, the amplifier produced a clean output signal with little ringing, indicating that it is well matched over a broad bandwidth.

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“…One study focusing on health-related Web sites indicated that seals of approval were relatively uncommon and were found in only 4.8% of sites examined (Hong, 2006). Seals of approval such as VeriSign and Trust e are created by third party organizations that set some standard or set of protocols for which the users of their seal apparently must follow, usually in relation to the handling of consumer information (Cantrell, 2000). Apparently, Web sites that conform to some set of standards can use an organization's seal, which is supposed to mean that some level of security and confidentiality is being met in collecting and maintaining consumer information by the site's operators so that information theft and inappropriate use of consumer information is reduced.…”

Section: Seals Of Approvalmentioning

confidence: 99%

Trusting the Internet

Wogalter

Mayhorn

2008

International Journal of Technology and Human Interaction

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Positive beliefs about the validity and reliability of website information are important for users and the success of a site. Users may use these beliefs in making judgments about the veracity of the informational content that they encounter on the Internet. This research examined several components associated with Web sites that could affect credibility beliefs about Web site information: domain suffixes (e.g., .com, .edu), quality seals, and organizations/domain names. Two studies were carried out involving a total of 433 participants. One had 247 participants (171 undergraduates and 76 non-student adults) and the other had 186 participants (89 undergraduates and 97 non-students). Results indicated that participants who reported spending greater time on the Internet showed significantly higher trust ratings on several components than those who reported spending less time on the Internet. Participants had difficulty discriminating between actual and fictitious quality seals and organization/domain names, with several fictitious ones judged as or more trustworthy than actual ones.

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Circuit to aid tuning of Class-E amplifier

Cited by 5 publications

References 6 publications

High linearity lead-lag style envelope modulator for RF power amplifiers

High linearity lead-lag style envelope modulator for RF power amplifiers

Broadband high‐power line driver with synthetic output impedance

Trusting the Internet

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