Broad band frequency reducer based on band-pass sigma-delta modulation
A down-converter and band-pass technology, applied in incremental modulation, image communication, color TV components, etc., can solve problems such as phase noise interference, achieve the effects of reducing bandwidth, reducing dynamic space, and avoiding analog mixing
Inactive Publication Date: 2008-07-09
RFDOT MICROELECTRONICS
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Problems solved by technology
The disadvantage of the digital-analog hybrid solution is that it requires an analog-to-digital converter (ADC) with a high dynamic space, and at the same time, due to the existence of a large number of out-of-band signals, the interference of phase noise is also very significant
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[0016] Below the present invention will be further described in conjunction with the embodiment in the accompanying drawing:
[0017] The present invention mainly consists of a low-noise preamplifier 11, an anti-aliasing low-frequency filter 12, a band-pass Σ-Δ modulation circuit 13 (Σ-Δ analog-to-digital converter ADC), a first adder 21, a band-pass filter 22, The second adder 23, a band-pass filter 24, a 1-bit comparator 25, a 1-bit DAC 26, a digital filter and a sampling circuit 27 are composed.
[0018] As shown in Figure 1: the input signal obtained from the antenna is input to the low-noise preamplifier 11, and the output end of the low-noise preamplifier 11 is connected to the input end of the anti-aliasing low-frequency filter 12, and processed by the low-noise preamplifier 11 The signal of the signal input to this wide bandwidth anti-aliasing low-frequency filter 12, the output end of anti-aliasing low-frequency filter 12 is connected with the input end of band-pass Σ...
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The invention relates to a broadband frequency demultiplier based on modulation of bandpass Sigma-Delta, in particular to a broadband frequency demultiplier making use of modulation of bandpass Sigma-Delta to filter out-of-band-signal. The invention is characterized in that: the output end of a low noise preamplifier is connected with the input end of an anti-aliasing low-frequency filter; the output end of the anti-aliasing low-frequency filter is connected with the input end of a bandpass Sigma-Delta modulation circuit; an input signal obtained from an antenna is input to the low noise preamplifier, a signal processed by the low noise preamplifier is input to the anti-aliasing low-frequency filter, a signal processed by the anti-aliasing low-frequency filter is input to the bandpass Sigma-Delta modulation circuit to be modulated and the obtained signal output by the bandpass Sigma-Delta modulation circuit is a digital signal. The invention makes use of bandpass Sigma-Delta ADC to sample an input signal, directly introduces an analog signal into a digital domain, thereby avoiding analog mixing; meanwhile, the bandpass modulation reduces the bandwidth of the input signal, thereby reducing dynamic space of Sigma-Delta ADC.
Description
technical field [0001] The invention relates to a broadband frequency down-converter based on band-pass Σ-Δ modulation, in particular to filtering out-of-band signals by using the broadband down-frequency device with band-pass Σ-Δ modulation. Background technique [0002] In the prior art, there are two main difficulties in the integration of a broadband downconverter for digital TV (digital TV) in chips: a purely analog solution requires a high dynamic space mixer (High Dynamic Range Mixer), at the same time to solve the problem of harmonic interference (HarmonicInterference). Because the usual mixer uses a square wave instead of a harmonic signal, it is inevitable to introduce odd harmonic interference. At the same time, due to the high difficulty of integrating large-parameter analog devices, the analog filter is also a relatively difficult circuit component to integrate. The more successful circuit in the pure analog downconverter is the Super Heterodyne structure adop...
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IPC IPC(8): H04N5/44H03M3/02
Inventor 冯向光何广宏
Owner RFDOT MICROELECTRONICS