Background technology
60GHz millimeter wave radio communication up to the transmission rate of 4Gbps and the bandwidth of 5GHz, becomes the one preferred technique of ultrahigh speed Wireless Personal Network of future generation with it, especially without field of consumer electronics such as compression HD video wireless transmission, has huge market prospects.60GHz technology has become international study hotspot, and Chinese 60GHz millimeter wave radio communication is divided into two frequency range 42.3-48.4GHz and 59-64GHz frequency range, and order the first two frequency range is all open.
The advantage of 60GHz radio communication is the transmission rate that can realize up to Gbps magnitude.This technology will become the mainstream technology of ultrahigh speed Wireless Personal Network.NEC, Samsung, HeLGDeng consumer electronics manufacturer of Panasonic have jointly set up WirelessHD alliance and have promoted 60GHz technology in the application without in the transmission of compression HD video, as seen its huge market potential at present.Current 60GHz technology in the world becomes the focus of academia and industrial quarters concern, ISSCC (International Solid State Circuits Conference) is offered every year special topic and is collected the relevant paper of 60GHz technology, and all many-sided difficult points such as the design of 60GHz millimetre-wave circuit, test are subject to extensive concern.At present the 60GHz frequency spectrum of China is open, but because technical difficulty is larger, for the application study of this frequency range substantially in blank.
Frequency divider is the important component part of phase-locked loop circuit.In the module of all phase-locked loop circuits, divider circuit is operated in highest frequency, makes the design of frequency divider become challenge.Injection locking frequency divider is applicable to high-frequency range and low-power consumption, and this is that it has advantages of and compares other frequency dividers, and needing the problem solving is to expand lock-in range.Compare with the frequency divider that is operated in low frequency frequency range, the desiging frequency divider that is applied to 60GHz frequency range has following difficult point: 1, operating frequency is high; 2, require wide lock-in range; 3, require low-power consumption; 4, to quadrature little.Therefore, the design of the frequency divider of wide lock-in range is current research focus and difficult point.
Summary of the invention
(1) technical problem that will solve
In view of this, main purpose of the present invention is to provide a kind of injection locking frequency divider of wide lock-in range, to expand the lock-in range of frequency divider, meets the requirement that is applicable to 60GHz Millimeter-wave Wireless Communication System:.
(2) technical scheme
For achieving the above object, the invention provides a kind of injection locking frequency divider of wide lock-in range, comprise and inject transistor 1, the first LC oscillator 2 and the second LC oscillator 3, wherein: the in-phase output end short circuit of the first LC oscillator 2 and the second LC oscillator 3; This injects grid access direct voltage biasing and the two frequency multiplication Injection Signals of transistor 1, and the source electrode of this injection transistor 1 and drain electrode are connected to the difference output end of the first LC oscillator 2 and the second LC oscillator 3, realize divide-by-two function.
In such scheme, described the first LC oscillator 2 and described the second LC oscillator 3 are identical two LC oscillator.
In such scheme, the in-phase output end short circuit of described the first LC oscillator 2 and the second LC oscillator 3, the OUTP output of the first LC oscillator 2 and the OUTP output short circuit of the second LC oscillator 3, the OUTN output short circuit of the OUTN output of the first LC oscillator 2 and the second LC oscillator 3.
In such scheme, by injecting the mixer action of transistor 1, output signal frequency is followed the tracks of Injection Signal frequency change, and realizing Injection Signal frequency is the wide lock-in range of 49~81GHz, produces differential output signal.
(3) beneficial effect
The injection locking frequency divider of wide lock-in range provided by the invention, by the in-phase output end of two identical LC oscillator is joined, inject the difference output end that transistorized source electrode and drain electrode are connected on respectively two oscillators, thereby realize the novel injection locking frequency divider structure of divide-by-two function, the wide lock-in range that to have realized Injection Signal frequency be 49~81GHz, can be applicable to 60GHz Millimeter-wave Wireless Communication System:.
Embodiment
For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.
In traditional injection locking frequency divider, as shown in Figure 1, transistor 1 is injected in difference output end access in cross-coupled pair LC oscillator, injects grid access direct voltage biasing and the Injection Signal of transistor 1, difference output end output difference sub-signal OUTP and the OUTN of oscillator 2.
According to injection locking principle, inject transistor and be equivalent to frequency mixer, inductor capacitor resonant circuit is equivalent to filter.When the resonance frequency of inductor capacitor resonant circuit is at ω
0when neighbouring, if inject transistorized grid frequency input signal ω=2 ω
0, inject transistor and amass existence is positioned to ω as the mixing of frequency mixer generation
0the mixing item at frequency place.If now circuit meets the needed phase-shift phase of Barkhausen's criterion, this circuit just can produce stable oscillation output signal so, and output signal frequency is half of Injection Signal frequency, thereby realizes divide-by-two function.Frequency of oscillation, by following the tracks of the variation of frequency input signal, remains two divided-frequency relation in lock-in range.When circuit no longer meets the required phase-shift phase of Barkhausen's criterion, circuit loses locking.
Inject transistor and be counted as a frequency mixer, the Voltage-output that inductance capacitance resonant cavity can be frequency divider by the current conversion of frequency mixer output.The behavioral scaling model of injection locking frequency divider as shown in Figure 2.Frequency mixer time can be introduced a phase shift α in work like this, and for guaranteeing that loop can steady operation, resonant circuit will depart from original resonance point and make the two add up to zero, alpha+beta=0 to introduce another one phase shift β.
Inject transistor and when direct current and two frequency multiplication signal injections, there is different phase response.When direct current injects, frequency mixer can not introduced phase shift, i.e. α=0, divider circuit can resonance at original frequency place; During two frequency multiplication signal injections, frequency mixer can be introduced phase shift
the resonance point of divider circuit can be offset, and resonant circuit is introduced phase shift
making total phase-shift phase is zero.The phase shift that can introduce due to resonant circuit is limited, is guaranteeing that under the prerequisite of loop stability, the frequency shift (FS) of resonance point is also limited, has limited the lock-in range of frequency divider.Inject transistorized model as shown in Figure 3.
As shown in Figure 4, the invention provides a kind of injection locking frequency divider of wide lock-in range, comprise and inject transistor 1, the first LC oscillator 2 and the second LC oscillator 3, wherein: the in-phase output end short circuit of the first LC oscillator 2 and the second LC oscillator 3; This injects grid access direct voltage biasing and the two frequency multiplication Injection Signals of transistor 1, and the source electrode of this injection transistor 1 and drain electrode are connected to the difference output end of the first LC oscillator 2 and the second LC oscillator 3, realize divide-by-two function.
In Fig. 4, the first LC oscillator 2 and the second LC oscillator 3 are identical two LC oscillator.The in-phase output end short circuit of the first LC oscillator 2 and the second LC oscillator 3, the OUTP output of the first LC oscillator 2 and the OUTP output short circuit of the second LC oscillator 3, the OUTN output short circuit of the OUTN output of the first LC oscillator 2 and the second LC oscillator 3.By injecting the mixer action of transistor 1, output signal frequency is followed the tracks of Injection Signal frequency change, and realizing Injection Signal frequency is the wide lock-in range of 49~81GHz, produces differential output signal.
In the injection locking frequency divider of wide lock-in range provided by the invention, as shown in Figure 4, adopt two identical LC oscillator, their OUTP and OUTN outputs are separately shorted together, inject transistorized source electrode and be connected on respectively OUTP and OUTN output with drain electrode, inject transistorized grid access direct voltage biasing and two frequency multiplication Injection Signals.When Injection Signal frequency is within the specific limits time, the differential signal of output output 1/2nd injected frequencies of oscillator, circuit is realized divide-by-two function.Theoretical according to phase shift compensation, owing to having adopted two identical oscillators, when two frequency multiplication signal injections, each oscillator only need to be contributed the phase shift of half
make total phase-shift phase be
compensated the phase shift that frequency mixer is introduced
the phase shift that makes whole loop is 0.Like this, when frequency mixer is introduced phase shift α, the phase shift total amount that resonant circuit can compensate will improve greatly, thereby the lock-in range of frequency divider is improved greatly.This frequency divider has been realized the wide lock-in range that Injection Signal frequency range is 49~81GHz.
The injection locking frequency divider of wide lock-in range provided by the invention, by injection leakage the two poles of the earth, transistorized source being received respectively to the difference output end of two identical LC oscillator, can realize Injection Signal frequency is the wide lock-in range of 49~81GHz; By adjustment, inject transistorized breadth length ratio, can effectively realize moving of wide locking frequency scope.This injection locking frequency divider is exported two paths of differential signals, can be used as the frequency divider of high frequency phase-locked loop circuit.
Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the foregoing is only specific embodiments of the invention; be not limited to the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.