Figure 1 - uploaded by Ahmed Raza
Content may be subject to copyright.
Source publication
This paper proposes a novel operational amplifier (OPA) voltage-controlled oscillator (VCO) circuits on the basis of impedance converters. The VCO can operate over a frequency range exceeding unity-gain bandwidth due to the location of the tank circuit, not at the output of the OPA, but at the noninverting input. The paper presents the mathematical...
Contexts in source publication
Context 1
... modeling, simulation, and prototype implementation of the proposed oscillators are given. Figure 1 shows the general VCO electronic diagram. The circuit inside the dashed rectangular is the negative impedance converter. ...
Context 2
... the circuit of Figure 1, inductor L and two contrary connected varactors VR1 and VR2 present the tank circuit of the VCO. Resistor Rdc isolates the dc control voltage line from the VCO tank. ...
Context 3
... can be seen in Figure 1, the tank circuit is connected to the noninverting input of the OPA rather than its output. This feature of the proposed VCO allows extending operation frequency range beyond the unity-gain bandwidth of OPA. Figure 2 shows VCO circuits based on impedance converters with two inductors and one capacitor. ...
Context 4
... Figure 10a illustrates the location of currents Itank and Ires in the VCO tank circuit. Therefore, the loaded quality factor can be calculated by the following equation: ...
Context 5
... by substitution of Vtriangle and QL into Equation (21), we calculate that |Vout,1| = 2.76 V. So, the relative error of amplitude calculation by Equation (21) is only 13.5%. Figure 10b shows the VCO tuning characteristics. As we can see in Figure 10b, the VCO operates from 830 MHz to 1.429 GHz, i.e., the tunable band is 599 MHz. ...
Context 6
... 10b shows the VCO tuning characteristics. As we can see in Figure 10b, the VCO operates from 830 MHz to 1.429 GHz, i.e., the tunable band is 599 MHz. Thus, the designed circuit is a wideband VCO, which operates in the frequency range, significantly exceeding the bandwidth of the OPA. ...
Context 7
... by using the proposed VCO topology, we can increase the maximum operating frequency by more than 22 times. Figure 11 shows the simulated power spectrum of the designed VCO at the lowest frequency (a) and the highest frequency (b). As we can see in Figure 11a, only the second and third harmonics contribute to the THD because the fourth and subsequent harmonics attenuated for at least 90 dB compared to the first harmonic. ...
Context 8
... 11 shows the simulated power spectrum of the designed VCO at the lowest frequency (a) and the highest frequency (b). As we can see in Figure 11a, only the second and third harmonics contribute to the THD because the fourth and subsequent harmonics attenuated for at least 90 dB compared to the first harmonic. By analyzing Figure 11b, we find that the second and upper harmonics decrease slowly. ...
Context 9
... we can see in Figure 11a, only the second and third harmonics contribute to the THD because the fourth and subsequent harmonics attenuated for at least 90 dB compared to the first harmonic. By analyzing Figure 11b, we find that the second and upper harmonics decrease slowly. However, the second and other harmonics attenuated by at least 36 dB. ...
Context 10
... to Reference [7], the noise figure of OPA LMH6629MF is 8 dB. Figure 11a,b shows that Pout = 9 dBm when Vdc = 1 V and Pout = 11 dBm when Vdc = 11 V. Figure 10b indicates that the minimum frequency of oscillations is 830 MHz, and the maximum is 1429 MHz. From Reference [7] (p.15, Figure 28) we find that fc = 4 kHz. ...
Context 11
... PN is the phase noise (dBc/Hz), F is the noise figure of the oscillator active device (dB), í µí± í µ 1.38 10 is the Boltzmann constant (J/K), T is the temperature in Kelvin, Pout is the oscillator output power, ffun is the frequency of oscillations (Hz), fc is the 1/f corner frequency of active device (Hz), and fm is the offset frequency (Hz). According to Reference [7], the noise figure of OPA LMH6629MF is 8 dB. Figure 11a,b shows that Pout = 9 dBm when Vdc = 1 V and Pout = 11 dBm when Vdc = 11 V. Figure 10b indicates that the minimum frequency of oscillations is 830 MHz, and the maximum is 1429 MHz. From Reference [7] (p.15, Figure 28) we find that fc = 4 kHz. ...
Context 12
... loaded quality factor, QL, is 8.5 and 2.6 for Vdc = 1 V and 11 V, respectively. Figure 12 shows the dependence of the phase noise versus offset frequency for the VCO shown in Figure 7. As can be seen in Figure 12, the VCO phase noise changes from −153.4 dBc/Hz to −139.3 dBc/Hz at 100 kHz offset frequency when the control voltage varies from 1 V to 11 V. Thus, the maximum in-band phase noise is −139.3 ...
Context 13
... 12 shows the dependence of the phase noise versus offset frequency for the VCO shown in Figure 7. As can be seen in Figure 12, the VCO phase noise changes from −153.4 dBc/Hz to −139.3 dBc/Hz at 100 kHz offset frequency when the control voltage varies from 1 V to 11 V. Thus, the maximum in-band phase noise is −139.3 dBc/Hz at fm = 100 kHz. ...
Context 14
... fabricated a prototype of oscillator circuit shown in Figure 2b. Figure 13 shows a PCB assembly of the oscillator. We selected OPA LMH6624 (Texas Instruments) with a slew rate of 350 V/μs, gain bandwidth of 1.5 GHz, supply voltage ±5 V, and the following passive components: L0 = 200 nH (2 × ELJRFR10), L = 8.2 nH (high-quality coil ELJQF8N2), and C1 = 2.2 pF (ceramic capacitor C0603C0G1E2R2C030BA). ...
Context 15
... used RF probes P-20A (Auburn Technology) to connect the oscillator output through a capacitive divider to the spectrum analyzer. Figure 14 shows the block diagram of the measurement experiment. Figure 15 shows the connection between the core elements of the measurement block diagram. ...
Context 16
... 14 shows the block diagram of the measurement experiment. Figure 15 shows the connection between the core elements of the measurement block diagram. The 2-channel power supply HMC8042-G (Rohde and Schwarz) is not shown in Figure 15. Figure 16 shows the measured power spectrum. ...
Context 17
... 15 shows the connection between the core elements of the measurement block diagram. The 2-channel power supply HMC8042-G (Rohde and Schwarz) is not shown in Figure 15. Figure 16 shows the measured power spectrum. ...
Context 18
... 2-channel power supply HMC8042-G (Rohde and Schwarz) is not shown in Figure 15. Figure 16 shows the measured power spectrum. As we can see in Figure 16, the frequency of oscillations is 583.1 MHz. ...
Context 19
... 2-channel power supply HMC8042-G (Rohde and Schwarz) is not shown in Figure 15. Figure 16 shows the measured power spectrum. As we can see in Figure 16, the frequency of oscillations is 583.1 MHz. The measured power is −43.9 dBm. ...
Context 20
... modeling, simulation, and prototype implementation of the proposed oscillators are given. Figure 1 shows the general VCO electronic diagram. The circuit inside the dashed rectangular is the negative impedance converter. ...
Context 21
... the circuit of Figure 1, inductor L and two contrary connected varactors VR1 and VR2 present the tank circuit of the VCO. Resistor Rdc isolates the dc control voltage line from the VCO tank. ...
Context 22
... can be seen in Figure 1, the tank circuit is connected to the noninverting input of the OPA rather than its output. This feature of the proposed VCO allows extending operation frequency range beyond the unity-gain bandwidth of OPA. Figure 2 shows VCO circuits based on impedance converters with two inductors and one capacitor. ...
Context 23
... Figure 10a illustrates the location of currents Itank and Ires in the VCO tank circuit. Therefore, the loaded quality factor can be calculated by the following equation: ...
Context 24
... by substitution of Vtriangle and QL into Equation (21), we calculate that |Vout,1| = 2.76 V. So, the relative error of amplitude calculation by Equation (21) is only 13.5%. Figure 10b shows the VCO tuning characteristics. As we can see in Figure 10b, the VCO operates from 830 MHz to 1.429 GHz, i.e., the tunable band is 599 MHz. ...
Context 25
... 10b shows the VCO tuning characteristics. As we can see in Figure 10b, the VCO operates from 830 MHz to 1.429 GHz, i.e., the tunable band is 599 MHz. Thus, the designed circuit is a wideband VCO, which operates in the frequency range, significantly exceeding the bandwidth of the OPA. ...
Context 26
... by using the proposed VCO topology, we can increase the maximum operating frequency by more than 22 times. Figure 11 shows the simulated power spectrum of the designed VCO at the lowest frequency (a) and the highest frequency (b). As we can see in Figure 11a, only the second and third harmonics contribute to the THD because the fourth and subsequent harmonics attenuated for at least 90 dB compared to the first harmonic. ...
Context 27
... 11 shows the simulated power spectrum of the designed VCO at the lowest frequency (a) and the highest frequency (b). As we can see in Figure 11a, only the second and third harmonics contribute to the THD because the fourth and subsequent harmonics attenuated for at least 90 dB compared to the first harmonic. By analyzing Figure 11b, we find that the second and upper harmonics decrease slowly. ...
Context 28
... we can see in Figure 11a, only the second and third harmonics contribute to the THD because the fourth and subsequent harmonics attenuated for at least 90 dB compared to the first harmonic. By analyzing Figure 11b, we find that the second and upper harmonics decrease slowly. However, the second and other harmonics attenuated by at least 36 dB. ...
Context 29
... to Reference [7], the noise figure of OPA LMH6629MF is 8 dB. Figure 11a,b shows that Pout = 9 dBm when Vdc = 1 V and Pout = 11 dBm when Vdc = 11 V. Figure 10b indicates that the minimum frequency of oscillations is 830 MHz, and the maximum is 1429 MHz. From Reference [7] (p.15, Figure 28) we find that fc = 4 kHz. ...
Context 30
... PN is the phase noise (dBc/Hz), F is the noise figure of the oscillator active device (dB), í µí± í µ 1.38 10 is the Boltzmann constant (J/K), T is the temperature in Kelvin, Pout is the oscillator output power, ffun is the frequency of oscillations (Hz), fc is the 1/f corner frequency of active device (Hz), and fm is the offset frequency (Hz). According to Reference [7], the noise figure of OPA LMH6629MF is 8 dB. Figure 11a,b shows that Pout = 9 dBm when Vdc = 1 V and Pout = 11 dBm when Vdc = 11 V. Figure 10b indicates that the minimum frequency of oscillations is 830 MHz, and the maximum is 1429 MHz. From Reference [7] (p.15, Figure 28) we find that fc = 4 kHz. ...
Context 31
... loaded quality factor, QL, is 8.5 and 2.6 for Vdc = 1 V and 11 V, respectively. Figure 12 shows the dependence of the phase noise versus offset frequency for the VCO shown in Figure 7. As can be seen in Figure 12, the VCO phase noise changes from −153.4 dBc/Hz to −139.3 dBc/Hz at 100 kHz offset frequency when the control voltage varies from 1 V to 11 V. Thus, the maximum in-band phase noise is −139.3 ...
Context 32
... 12 shows the dependence of the phase noise versus offset frequency for the VCO shown in Figure 7. As can be seen in Figure 12, the VCO phase noise changes from −153.4 dBc/Hz to −139.3 dBc/Hz at 100 kHz offset frequency when the control voltage varies from 1 V to 11 V. Thus, the maximum in-band phase noise is −139.3 dBc/Hz at fm = 100 kHz. ...
Context 33
... fabricated a prototype of oscillator circuit shown in Figure 2b. Figure 13 shows a PCB assembly of the oscillator. We selected OPA LMH6624 (Texas Instruments) with a slew rate of 350 V/μs, gain bandwidth of 1.5 GHz, supply voltage ±5 V, and the following passive components: L0 = 200 nH (2 × ELJRFR10), L = 8.2 nH (high-quality coil ELJQF8N2), and C1 = 2.2 pF (ceramic capacitor C0603C0G1E2R2C030BA). ...
Context 34
... used RF probes P-20A (Auburn Technology) to connect the oscillator output through a capacitive divider to the spectrum analyzer. Figure 14 shows the block diagram of the measurement experiment. Figure 15 shows the connection between the core elements of the measurement block diagram. ...
Context 35
... 14 shows the block diagram of the measurement experiment. Figure 15 shows the connection between the core elements of the measurement block diagram. The 2-channel power supply HMC8042-G (Rohde and Schwarz) is not shown in Figure 15. Figure 16 shows the measured power spectrum. ...
Context 36
... 15 shows the connection between the core elements of the measurement block diagram. The 2-channel power supply HMC8042-G (Rohde and Schwarz) is not shown in Figure 15. Figure 16 shows the measured power spectrum. ...
Context 37
... 2-channel power supply HMC8042-G (Rohde and Schwarz) is not shown in Figure 15. Figure 16 shows the measured power spectrum. As we can see in Figure 16, the frequency of oscillations is 583.1 MHz. ...
Similar publications
The concept of exceptional point of degeneracy (EPD) is used to conceive a degenerate synchronization regime that is able to enhance the level of output power and power conversion efficiency for backward wave oscillators (BWOs) operating at millimeter-wave and Terahertz frequencies. Standard BWOs operating at such high frequency ranges typically ge...
